Fasting is a core spiritual discipline along with prayer, scripture reading and meditation, yet probably one of the least understood and least practiced despite it's powerful impact on our spiritual lives. In this article we will go through scripture and reveal some amazing insights as well as dispel some misconceptions. You'll likely never look at fasting, or your body, the same way again.
Part 1: The Tale of Two Dogs
A Native American elder once described his own inner struggles in this manner: “Inside of me there are two dogs. One of the dogs is evil. The other dog is good. The evil dog fights the good dog all the time.” When asked which dog wins, he reflected a moment and replied, “The one I feed the most.”
This wise tale has been circulated in various forms for at least half a century, often attributed to the Cherokee among other Native American tribes. Famous writers and speakers such as George Bernard Shaw and Billy Graham have used this poetic analogy, but here I wish to make use of it once again as I can think of no other story which illustrates our modern concept of fasting so succinctly. Paul parallels this concept of a war within us in the book of Romans.
For we know that the law is spiritual, but I am of the flesh, sold under sin. For I do not understand my own actions. For I do not do what I want, but I do the very thing I hate. Now if I do what I do not want, I agree with the law, that it is good. So now it is no longer I who do it, but sin that dwells within me. For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out. For I do not do the good I want, but the evil I do not want is what I keep on doing. Now if I do what I do not want, it is no longer I who do it, but sin that dwells within me. So I find it to be a law that when I want to do right, evil lies close at hand. For I delight in the law of God, in my inner being, but I see in my members another law waging war against the law of my mind and making me captive to the law of sin that dwells in my members. Wretched man that I am! Who will deliver me from this body of death? Thanks be to God through Jesus Christ our Lord! So then, I myself serve the law of God with my mind, but with my flesh I serve the law of sin. -Romans 7:14-25 (ESV)
The inner conflict of mankind appears to be universally recognized, though as we shall see, it is an issue that is handled and understood differently in various cultures and societies. How does this tie in with fasting you ask? May I submit that today, in our society, there are basically two views or interpretations of fasting; literal and symbolic. Both of these views however share a common denominator in that they understand fasting in a sense as “starving the evil dog."
The Literal Interpretation of Fasting
In this interpretation, fasting is viewed as a willful act of penance to “die to the flesh”. As food is for the stomach or the physical body and required to sustain it, fasting is quite literally starving the flesh to bring it into submission.
The Symbolic Interpretation of Fasting
In this interpretation, fasting is viewed as a general act of self-denial, not limited to food. The Catholic tradition of lent is the strongest example of this view as anything can be “given up” for a season including activities or pastimes as well as particular foods or beverages usually not critical for sustenance or survival.
In truth, neither of these views of fasting are really accurate, though each certainly have merit. To really understand the Hebrew concept of fasting, we’ll have to go beyond our cultural perceptions and look at scripture through a different lens. So hang on and bear with me as we take a trip back in time to unravel one of scripture’s most basic and critical spiritual disciplines which has nearly been lost through translation in the modern era.
Part 2: Differentiating Soul & Spirit
Translation is a tricky thing and words don’t always port over from one language to the next and keep their original meaning and connotations. In English, soul and spirit are often interchangeable in context– just look up both words in a dictionary and you’ll find how similarly even Mr. Webster defines them. This should come as no surprise in light of scripture:
For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart. -Hebrews 4:12 (ESV)
This is a pretty famous passage that is quoted often, but a few important elements are often overlooked. Here we are told that the word of God is sharper than any two-edged sword– but how sharp is that? Well, scripture elaborates by telling us that the word of God is so sharp, it can divide soul and spirit. Now why would this be a testament of how sharp God’s word is unless the author was acknowledging how difficult the two were to separate? Here we are shown that clearly defining the boundary between soul and spirit and being able to differentiate between the two was an issue long before English muddied the waters.
Picture in your mind one of those rubber band balls. Hundreds, possibly thousands of big rubber bands make up the ball, all overlapping and intertwined looking nearly impossible to differentiate one rubber band from another. Now imagine someone told you to separate the rubber bands into two categories. Well, how would one do that? What are the defining characteristics of each category and where would one start? Fortunately scripture brings some insight to this confusion.
The author of Hebrews claims that the word of God can divide or differentiate between soul and spirit, which begs the question… Does it? While we’re talking about differentiation, let me point out that there are two words used in New Testament Greek for the word “word”. This is a nonessential tangent but will be beneficial for our study.
Logos vs. Rhema
In the original Greek, there is the word logos, which is the written word and then there is rhema which is the spoken word. Both are rendered in English as simply “word” which is unfortunate. This particular passage in Hebrews uses logos, so the author claims that the written word of God (collectively known as scripture) has the ability to separate soul and spirit. Contrast this with another famous passage—Ephesians 6:17—which identifies the “sword of the Spirit” as “the word of God”, using the Greek rhema. While we often hold our Bibles firmly in our hands when we speak of this passage, we do so somewhat misguidedly as the author claimed the spoken, rather than written, word of God is the “sword of the Spirit”. This understanding of course is more congruent with the language of the context, as the role of the Spirit is to communicate what the Father says. So of course the “sword of the Spirit” would be the spoken word of God. Now this is a bit of a moot point as we believe all scripture is “God breathed” and “God inspired," meaning that before scripture was written by man it was spoken by God, so don’t think that your Bible can’t be the sword of the Spirit, but rather be aware of the meaning of this passage.
The logos (scripture) is exhaustive in its content covering a broad range of topics, teachings, history, lineages and materials. It is an ocean of information which often can be a chore to sift through. This is where rhema comes in. God often speaks by leading us to a relevant portion of scripture which brings light to our current situation or circumstance. This is an example of God’s rhema or spoken word. Ephesians 6:17 wasn’t discounting the importance of the logos, but rather emphasizing how critical a relevant word from God is in our daily lives and in the battle against the enemy. When Jesus was in the wilderness fasting for 40 days and Satan came to tempt him into eating some bread, Jesus didn’t start quoting random scriptures to ward off the temptation, He quoted specific verses that brought insight and answers to the situation at hand. That is the power of rhema—the sword of the Spirit.
Of course the spoken word of God is not limited to scripture passages. God still speaks after all. He can speak to us through dreams, visions, an audible voice, through our thoughts and emotions, through other people and through circumstances just to name a few. But though God’s rhema isn’t limited to the logos, it is always in agreement with it. God cannot lie or break his word, therefore rhema cannot step outside the boundaries of or conflict with logos. But be encouraged that the only offensive weapon listed in Ephesians is not God’s logos—a large and unwieldy tome—but God’s rhema, which is a swift, sharp and agile word for whatever situation you may be in.
Back on Track
So we’ve established that Hebrews states that the logos is capable of dividing soul and spirit and we’ve been bold enough to seek out whether or not this claim is true and sure enough, right there in the very verse that makes the claim is the proof. The Greek word used here for soul is psuche and the word used for spirit is pneuma. While that information may not seem definitive to an English speaker, it spoke volumes to the Greek. Psuche is actually the Greek word that we derive our English word psyche from, meaning "the mind, behavior or personality of a person." The soul therefore can best be described as the mind, the will and the emotions—what essentially makes you, you.
Pneuma on the other hand is the Greek word in which we derive pneumatic from, which means “air powered”. Pneuma literally meant “air” or “breath”. This word tied in directly with the Old Testament Hebrew word for spirit—ruach—which literally meant “breath” or “wind” (see Gen 1:2, 1st Sam 16:14, Job 4:15, Pro 15:4 et al). This is essentially the supernatural element of life, the opposite of the carnal flesh. The flesh and the spirit are the two interfaces in which the soul can interact with the world around it. Your soul interacts with the physical realm through the flesh—its physical body, while it interacts with the spiritual or supernatural realm through the spirit.
This understanding of the spirit begs a few intriguing questions. For instance, does everyone have a spirit and therefore can anyone interact with the spiritual realm? Humanity seems to have some basic innate ability in this capacity, however scripture (and our own personal experience) would suggest that when we become believers and are “born again" this capacity is greatly increased or revived and renewed. Furthermore, the innate spirit of man is not of God according to scripture and honing our spiritual aptitude outside of God is known as witchcraft.
My current understanding of this complex and intricate enigma is that in the beginning, God made Adam (and Eve) in His image—a trinity; body, soul and spirit. However, the spirit God placed in man was his own, not the spirit of God. God placed the Tree of the Knowledge of Good and Evil in the midst of the garden and told Adam that if he ate of it, in that day he shall surely die. However when Adam took of the fruit, he didn’t die—did he? It is my belief that he did, for God is not a liar. I believe that Adam died a spiritual death that day and his original God-breathed spirit fell, just as the angels of Satan did, to a state which opposed God rather than was in harmony with God. In this opposed or fallen state, Adam was doomed to die an eternal death rather than have eternal life.
Therefore Adam didn’t lose his spirit, for man cannot undo what God created, but it was twisted and perverted into a state which was no longer usable by its maker. But God, in His infinite grace and wisdom, had already set in motion a plan to redeem the spirit of man from its decrepit and mortal state. When we believe in Jesus as the Christ, we therefore receive the Spirit of God as a substitute for our own fallen spirit. We see this new spiritual life first take place in John 20:22 where Jesus imparts the Holy Spirit to His disciples by breathing on them—copying what He had done thousands of years earlier in Genesis 2:7 when God breathed on a pile of dust and made man a living being. Except this time the breath of God (remember breath is ruach/pneuma, or spirit) was breathing new life into man. It is in John 20:22 that the disciples are transformed from Jews to Christians (though the term wasn’t coined yet) as they received the indwelling of the Spirit of God, transferred from the only source of life by His breath from His spirit to theirs. This event is not to be confused with the “baptism” of the Holy Spirit which would not happen until Pentecost after Jesus ascended unto heaven as recorded in Acts chapter 1 and 2. This leads us to another slightly off topic but nonetheless important tangent—the power of prepositions in scripture.
With, In & Upon
Prepositions are important when reading any text, but they are critical when reading scripture. The three (naturally) prepositions we need to watch out for when reading about the Spirit of God in scripture are with, in and upon. God’s spirit can be with anyone or anything, as with only implies God’s presence and God is omnipresent after all. God’s spirit can likewise be upon anyone or anything—for example, Samson and Balaam’s donkey. Upon implies the supernatural power of God. However God’s spirit can only be in a believer as the two are intrinsically intertwined—you can’t have one without the other. In is the indwelling or peace of God.
The Spirit of God was with many people in the Old and New Testaments, both Jew and Gentile. The Spirit of God was upon only a select few in the Old Testament—namely prophets, priests and kings. After Pentecost, this exclusive list broadened considerably—we as believers all have access now. The Spirit of God wasn’t in anyone until John 20:22, but was foretold by the prophet Jeremiah (Jer 31:31-34). Looking back at the creation of man, Genesis indeed distinguishes between the spirit given to Adam and the Spirit of God. The word used of the Holy Spirit in Genesis (see Gen 1:2) is the Hebrew word ruach while the word used for the spirit of man is n’shamah (see Gen 2:7). Paul highlights this distinction in 1st Corinthians (see below). Therefore as believers we have access to God in a way that Adam never did. God's redemption didn't just restore us to Adam's original state, it infinitely improved upon it.
The earth was without form and void, and darkness was over the face of the deep. And the Spirit (ruach) of God was hovering over the face of the waters. -Gen 1:2 (ESV)
then the LORD God formed the man of dust from the ground and breathed into his nostrils the breath (n’shamah) of life, and the man became a living creature. -Gen 2:7 (ESV)
Thus it is written, "The first man Adam became a living being"; the last Adam became a life-giving spirit.
-1 Co 15:45 (ESV)
And when he had said this, He breathed on them and said to them, "Receive the Holy Spirit.”
-John 20:22 (ESV)
Theologically, there are three phases of salvation: justification, sanctification and glorification. This process also clearly distinguishes between spirit, soul and body and shows that God's redemptive plan is completely holistic. The first phase of salvation is justification—the renewal of the spirit which comes instantly when you profess your faith in Christ. The next phase is sanctification—the renewing of your soul (mind will and emotions). This phase is not instant nor is it easy, rather it takes a lifetime of discipleship, sacrifice and obedience. The final phase of salvation is glorification—the renewing of your body. This only happens after Christ's return and the final judgment when the new heavens and new earth are created. The most extensive passage on this latter doctrine can be found in 1st Corinthians chapter 15 but the only hints we truly get from scripture of what a glorified body actually looks like is in Christ's after His resurrection.
Part 3: Location, Location, Location
Our Western understanding of the location of the soul and spirit comes from Greek philosophy which of course also impacted the New Testament writings. However the Hebrew understanding was much different. In the Western world today, we have been inundated with so much information from so many different sources, cultures and traditions, that we often can’t pinpoint why, or even what, we believe. Ask the average American where the soul resides and you’ll likely get several different answers. However if you ask where the psyche resides, most would point to their heads. Likewise, if you were to ask where the spirit resides you might get a few different answers. Even Christians get a bit perplexed at the question. However the question shouldn't be nearly as complicated as we think as every adult who speaks to a child in Sunday school knows the answer—as New Testament believers we have asked Jesus (though technically the Holy Spirit as Jesus’ location is at the right hand of the Father) into our hearts.
The New Testament Greek concept of the heart was that it was the center of both physical and spiritual life, the innermost part—the soul and spirit. Look at Hebrews 4:12 again. It says that the word of God is able to judge the thoughts and intentions of the heart. The Greek word used here is kardia, which is still the word used in the English medical field for the heart. However even most grade school students would say that the heart doesn’t think, nor does it have intentions—those are functions of the soul or mind.
Despite this conflict with our modern medical understanding of human anatomy, we in the Western world are so influenced by Greek philosophy that we still often correlate some functions of the soul with our heart. Particularly we associate feelings, personality and morality with our heart. If we are in love we say someone has captured our heart. If we are sad we say something broke our heart. If we have dreams and aspirations, we say we have to follow our heart. If someone is particularly moral, we say they have a pure heart. Other descriptive phrases of people include brave-hearted, kind-hearted, hard-hearted, black-hearted etc. So despite your education insisting your soul resides in your head, our cultural tradition tells us that our heart has something to do with it. This cultural belief is so prevalent, that in English Bibles, translators render both New and Old Testament words speaking of the soul or spirit as heart due to the Greek philosophy that your heart is home to both.
But this understanding of the location of the soul and spirit was not always so. While the New Testament is heavily influenced by Greek thought, the Old Testament is almost completely written in Hebraic thought and tradition which was founded on a very different understanding of God and the universe. In the Hebrew understanding, the seat of all physical and spiritual life was in the center of your physical body—your belly. In the Old Testament there are actually two words we translate as “heart”—leb and lebab. Leb literally means “center” or “middle”, while lebab means “most interior organ." The Hebrew understanding was that your gut was the home of your soul and spirit. This idea is stated a few times in scripture, but the original terms have been lost through translation.
The spirit of man is the lamp of the LORD, searching all his innermost parts. -Pro 20:27 (ESV)
While the ESV translates it “innermost parts” and the NASB renders it “innermost being," as we travel back in time it gets closer to the original language. The KJV (1611) translates it as “inward parts of the belly” and the Geneva Bible (1587) renders it beautifully as “The light of the Lorde is the breath of man, and searcheth all the bowels of the belly.”
Keep your heart with all vigilance, for from it flow the springs of life. -Pro 4:23 (ESV)
Here the ESV as well as just about every other translation, including the KJV, the Geneva, and even the Bishop’s Bible before it (1568), render leb as "heart." What is interesting is that Jesus quotes this very proverb in the book of John:
“Whoever believes in me, as the Scripture has said, 'Out of his heart will flow rivers of living water.'" -John 7:38 (ESV)
This is interesting because despite many modern translations rendering the key word here as “heart” in order to maintain consistency, Jesus is quoting an Old Testament proverb (written in Hebrew) but He is speaking in Greek. So what is the Greek word Jesus used to translate the Hebrew word leb? He did not use kardia, meaning “heart," He used koilia, a Greek word meaning "abdomen, belly or womb!" Indeed the KJV throws consistency out the window and correctly translates Jesus’ words as “out of his belly shall flow rivers of living water.” The Geneva and Bishop’s Bible render koilia as “belly” as well while the NASB reverts back to “innermost being” and the NIV phrasing it even more generically as "from within him."
When he saw the crowds, he had compassion for them, because they were harassed and helpless, like sheep without a shepherd. -Matt 9:36 (ESV)
Here lies beneath the surface another telltale sign of the Hebrew understanding of the location of the soul and spirit. As we’ve established that emotions and feelings are often associated with the soul (even in the Greek understanding), here is a verse which describes Jesus as having a strong feeling—that of compassion. What is interesting is that the Greek word translated as “had compassion” in the ESV, “felt compassion” in the NASB and “moved with compassion” in the KJV, is splagchnizomai, which literally means "to have the bowels yearn." Translators opted to translate the meaning of the phrase rather than a more literal rendering as it would confuse modern readers. Indeed, some might even be offended that Jesus’ bowels yearned for someone. But regardless, this passage indicates that even in Greek, there were idioms that alluded to the seat of our emotions being in the belly.
Conclusion
We as Westerners easily identify with Greek philosophy, thought and tradition, however it is the Hebraic tradition which we must understand to fully comprehend scripture. While the Greek mindset was that our soul and spirit were seated in the heart, the Hebrew understanding was that your “inner man” resided in your belly. Proverbs therefore describes our spirit as being the lamp, light or candle of the Lord which searches, knows and explores every nook and cranny of your belly. The writer of Proverbs was saying that God’s spirit can communicate with your soul and spirit and therefore knows every thought, every intention and every dark corner which even you may not be consciously aware of.
Likewise, Proverbs instruct us to guard our bellies (I know, it sounds weird for a Greek thinker) as it is the center of all physical, emotional, mental and spiritual life. The idea here is that since the soul and spirit are so intertwined and both take up residence in your belly, you must not allow your soul to become tainted as it will contaminate your spirit as well. Think of a public swimming pool—if one person pees, everyone in the pool is affected. It is this proverb that Jesus played off of when He spoke of drinking living water and thirsting no more, speaking of His spirit as the ultimate “spring of life”.
Finally we see in Matthew an interesting figure of speech that again correlates the soul and the seat of emotion within the belly. This might sound odd at first, but even in our Greek biased culture we have similar idioms that tie the soul to the belly. Have you ever had a "gut feeling?" Maybe you’ve experienced “butterflies in your stomach” before, or have witnessed a “gut-wrenching” scene. Ever stop and ponder why some particularly shocking news or sight can make you feel "sick to your stomach?" Indeed science has recently called the belly “the second brain” as it was discovered that the stomach region has it’s own intricate nervous system which plays a critical role in our physical and mental well being. Named the enteric nervous system, it can work independently or in conjunction with the brain, affects your mood, can perceive danger and even influences subconscious thought. In fact, your stomach has more neurons than a dog's brain—in other words your gut is incredibly intelligent. It would seem those crazy Hebrews were onto something and that modern science is just now catching up...
Part 4: Implications of the Belly
The ramifications and implications of this location of the soul and spirit is nothing short of profound. But before we move forward I want to prove to you just how strong this belief was in the Jewish mindset. In the book of Matthew, we see Jesus re-teaching the disciples, breaking them out of their Old Testament ways.
“Do you not see that whatever goes into the mouth passes into the stomach and is expelled? But what comes out of the mouth proceeds from the heart, and this defiles a person. For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander. These are what defile a person. But to eat with unwashed hands does not defile anyone.”
-Matt 15:17-20 (ESV)
Here Jesus is grooming His disciples to walk by the spirit of the Law rather than by the letter. Being Jewish, they all held to their customs and traditions handed down to them from their forefathers, however they were lacking in understanding. They believed that in eating unclean foods—whether it was unclean by definition of the Law or unclean because they hadn’t prepared it properly or washed their hands according to the Law—they would taint their soul and spirit. Jesus therefore differentiated the stomach from the soul and spirit by calling the former the koilia (belly) and the latter the kardia (heart). Now Jesus wasn’t arguing the physical location of the soul and spirit, he was simply using language His disciples would understand to be able to differentiate between physically unclean and morally and spiritually unclean, because to the Jews, these were one and the same.
So now that we’ve thoroughly established the Hebraic understanding which came from the Old Testament Law (which God Himself set up), let’s explore some of the more interesting implications.
Original Sin
Remember that symbolism permeates the whole of scripture and certainly the story of the fall of creation is loaded with it. The Tree of the Knowledge of Good and Evil was certainly so. The Tree obviously symbolized something greater than itself and likewise so did eating from it—and therein lies a piece of the puzzle.
God told Adam and Eve not to eat from the tree. The tree symbolized the ability to judge between good and evil outside of God. Man ate of the tree in the hopes of bypassing God as the ultimate judge of right and wrong so that man could “do what was right in his own eyes”. Man’s spirit was trying to overthrow God’s just as Satan had attempted. So he ate. Sin entered into the world through the belly—both literally and figuratively. Therefore God punished all those guilty with a sentence befitting their crime—each receiving a curse involving their belly. He cursed the ground from which Adam was made so that man would now have to toil to feed his belly. He directly cursed the belly of the woman so that she would suffer pain in childbearing. Then He cursed the serpent so that he must crawl on his belly—sentenced to crawl around on his very soul.
The Second Adam
When God created man, He gave him an incredible power to re-create (procreate). Now while it is true that animals could mate and produce physical offspring, man was given the ability to create spiritual beings. In the belly of a woman lies both a physical and spiritual womb where the miracle of conception occurs. It is in the woman’s belly and therefore in her soul and spirit that a human is formed and since "like begets like," a child with a soul and spirit is conceived. Our understanding from scripture is that it was man, not woman, who ultimately bore the responsibility of sin and therefore it is through man that sin is passed on. Therefore when God came to Earth, He did so as a baby, formed in the physical and spiritual womb of the virgin Mary. God’s spirit reached out to Mary’s and conceived a child that was not of the lineage or spirit of Adam. Therefore Jesus was both fully God and fully man without being conceived in sin as all of mankind is. The best passage covering this reality is found in Romans chapter 5.
Behold, I was brought forth in iniquity, and in sin did my mother conceive me.
-Psa 51:5 (ESV)
Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned-- for sin indeed was in the world before the law was given, but sin is not counted where there is no law. Yet death reigned from Adam to Moses, even over those whose sinning was not like the transgression of Adam, who was a type of the one who was to come. But the free gift is not like the trespass. For if many died through one man's trespass, much more have the grace of God and the free gift by the grace of that one man Jesus Christ abounded for many. And the free gift is not like the result of that one man's sin. For the judgment following one trespass brought condemnation, but the free gift following many trespasses brought justification. For if, because of one man's trespass, death reigned through that one man, much more will those who receive the abundance of grace and the free gift of righteousness reign in life through the one man Jesus Christ. Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men. For as by the one man's disobedience the many were made sinners, so by the one man's obedience the many will be made righteous.
-Rom 5:12-19 (ESV)
Part 5: The Spiritual Discipline of Fasting
Now we come to our final point, indeed what this entire study has been building up to, understanding why we fast. We often view fasting as “starving” the evil dog to make him weaker, but the Jewish understanding was much more a competition of space. As the soul and spirit occupied the same physical space in your belly, the natural conclusion was in order to grow the one, you must shrink the other. Fasting was a discipline that gave the spirit man an opportunity to increase his boundaries, to swell up and to fill up the cavity of your belly without the restrictions of a full stomach. The Hebrew concept of fasting was literally to shrink the flesh to make more room for the spirit.
Fasting is therefore a spiritual discipline that seeks to bring the soul (the mind, the will and the emotions) into alignment with or submission to the will of God. It is not a tool of manipulation with which we can coerce God into coming into alignment with our will. Fasting will not get you that job promotion you’ve been wanting nor will it convince God you’re more spiritually mature than others and deserving of more blessings. Fasting is an act of humility, one which communicates, “God, I do not possess the means or capacity to do this deed or to live this life righteously– I need more of your Spirit to give me strength and wisdom.” Therefore fasting is not a bonus activity that counts as extra credit in our Christianity—it is a core discipline and essential for spiritual growth and maturity.
It has been said by many that fasting without prayer is just going hungry. This adage may be well intended, but communicates a misunderstanding of fasting. Notice that in both the Hebrew tsum and Greek nesteia, the word "fasting" simply means “to abstain from food” or “to hunger.” So if you replace the word "fasting" in that Christian adage with the actual meaning of the word, it sounds rather silly: “To hunger without prayer is just going hungry.” While it is true that fasting is enhanced by prayer and that prayer is usually (but not always) mentioned alongside fasting in scripture, fasting is its own spiritual discipline apart from prayer. Therefore you can fast without praying just as you can read the Bible without praying. Of course combining spiritual disciplines is both wise and beneficial, so fasting and praying is more powerful just as fasting and reading scripture or praying and reading scripture is. Fasting expands your spirit man and brings you more into alignment with the Spirit of God which subsequently enhances your prayer life because you will be praying purer prayers more in line with what is on God’s heart (oops, there’s that word again!) rather than what’s on yours. They become more spiritual prayers rather than fleshly prayers. Also, with a greater presence of the Holy Spirit in your inner man, scripture can come alive and deeper meaning and understanding can occur. You can see why fasting is its own spiritual discipline and one that needs to be practiced regularly–not just for special occasions.
And Jesus rebuked the demon, and it came out of him, and the boy was healed instantly. Then the disciples came to Jesus privately and said, "“Why could we not cast it out?" He said to them, "“Because of your little faith. For truly, I say to you, if you have faith like a grain of mustard seed, you will say to this mountain, 'Move from here to there,' and it will move, and nothing will be impossible for you. But this kind never comes out except by prayer and fasting.”
-Mat 17:18-21 (ESV)
It is important to note why the disciples were not able to cast out the demon here. Jesus explains that it was a lack of faith on their part, but also that prayer and fasting were required. This means that Jesus had been fasting and praying while the disciples had not—He was spiritually prepared while the disciples were spiritually unarmed. Here we see a link between fasting and faith in that the former leads to the latter. Expanding your spirit man and increasing your capacity for the indwelling of the Holy Spirit brings you more into alignment with the will of God and strengthens you and your ability to stand against the enemy. A natural consequence of being more attuned to the Holy Spirit is that you are more confident of what His will is and therefore have more faith to partner with Him to bring it to pass. Remember, Jesus only did what He saw the Father do (John 5:19). How did He know what the Father was doing and have the faith to bring it to pass? Through constant prayer and fasting. Note that prayer is comprised of listening as well as speaking.
Types of Fasts
Fasting is about expanding your spiritual capacity, not about "righteous dieting," so be sure your motives are pure. While weight loss and detoxing can be side effects of fasting, they are not the goal. That said, the modern day “Daniel fast” seems to attract health conscious Christians. The guidelines for this "partial fast" come from Daniel 1:12 and Daniel 10:3. While these guidelines do come from the same book and are therefore combined and coined the "Daniel fast," it is important to note that these two passages are plucked from two completely different contexts and neither are called fasts in the texts. This is significant as Daniel 9:3 does explicitly describe Daniel fasting. But Daniel 1:12 describes a 10 day test (not a fast) which prescribes a diet limited to vegetables and water (though modern practitioners also include fruits). Daniel 10:3 was a diet restriction that abstained from meat, wine and food additives such as salt or sugar. This restriction explicitly lasted 21 days.
The purpose of each of these diet restrictions was drastically different. The diet restrictions found in Daniel 1:12 are not a fast as their purpose was not to seek God, or even to hunger at all, but rather a test to prove to the king of Babylon that the Jewish men could eat a strict kosher diet (without defiling themselves with the unclean food found at the king’s table) and remain physically healthy. If kosher eating were considered fasting, then Jews would never have to call a fast as they were always doing it. Again, fasting (tsum) means "to hunger" with the literal meaning of the word meaning "to cover or shut one's mouth." Likewise, the diet restrictions found in Daniel 10:3 are not described as a fast, but as a Jewish mourning custom (see Dan 10:2) which also included abstaining from the use of oils and perfumes. These customs, like the use of sackcloth, ashes, tearing one's clothes, or ripping out the beard, communicated to others in that society that you were in a period of mourning, not fasting.
It should be noted that there aren’t any biblical passages that identify a partial fast—only traditions that describe dietary restrictions and other rituals and behaviors that accompany periods of mourning. As the customs are more focused on outward signs of grieving and the transition back into normal social behavior rather than a focus on seeking the Lord, it is difficult to categorize mourning rituals as fasting, but there may be some nuanced overlap in these categories. Regardless, it seems that the modern “Daniel fast” practice is presented as an entry point to actual biblical fasting while also promoting the health benefits of dieting and detoxing on a regular basis. None of that is bad mind you, but again, the concern of fasting is the spiritual, not physical benefits.
You may have noticed in scripture that there isn’t a clear set of guidelines on fasting. The clearest guideline is simply to not eat—anything. Therefore partial fasts are really not fasts at all as you’re either fasting or you’re not. A partial fast is a misnomer as the definition of the word fasting is “to abstain from food” or “to hunger”—neither of which are fulfilled through partial fasts as a belly full of vegetables or bread is still a full belly. There are also no strict guidelines of the length of a fast in scripture as the length of time is not what defines a fast, but rather the purpose of the abstention. However, as the length of a fast increases, so does the impact on the spirit man. Due to the basic definition of fasting, technically a fast can be as short as a single meal as an empty stomach is an empty stomach. But a prolonged fast has a greater impact. Think in physical terms here—as you go without food, over time the stomach begins to shrink. So a short fast empties the stomach, giving more room for the spirit man in the short term while a long fast literally shrinks the stomach giving more room for the spirit man in the long term.
There are both physical and biblical upper limits to the length of this discipline. Most biblical fasts lasted one, three or seven days with the longest fast without water being three days. The most common biblical fast was a single day (24 hours) without food or water. The only exceptions were three men in all of scripture who fasted for forty days (Moses, Elijah and Jesus) and one who fasted for an astounding eighty days (Moses again—Deut 9:9-18). It is important to note that these extended fasts (greater than seven days) were unique in that God called them to the fast and sustained their bodies through it—it is not possible to survive an eighty day fast without food or water without supernatural aid. So with these few exceptions to the rule duly noted, typically water was viewed as permissible during a fast—particularly for fasts lasting longer than 3 days.
However some people “supplement” their fasts with fruit juice or other liquid energy sources. This is cheating a bit and circumventing the purpose of fasting so I’ll simply say that if at all possible, just drink water or simply limit your fasts to 1-3 days so that you can function (fairly) normally without the aid of supplements. There are no heavenly bonuses for personal fasting records, so focus on quality and regularity rather than half-hearted (there's that language again) attempts for bragging rights. Also know that a forty day fast is not like a trip to Mecca—it is not some ultimate spiritual goal that one must achieve in life. Forty day fasts were incredibly rare in scripture, not the norm. Again, the norm was 24 hours without food or water. Less common were three day fasts and less common still were seven day fasts.
Despite the exclusive link between fasting and food found in both the Hebrew and Greek words and practices, in modern times we have applied a general definition to the term as simply “giving something up.” So someone might “fast” from TV for a week while another “fasts” from soda for a month. These practices have historically derived from Catholic Lent however, not biblical fasting. So while sacrifice, dying to self, caring for the temple of the Holy Spirit and prioritizing spiritual activities over carnal ones are all good, solid, biblical principles, they are not substitutes for fasting. Prayer, fasting, studying the Word of God, discipleship, evangelism, tithing etc. are all spiritual disciplines and requirements—you can’t opt out of them or substitute something else in their place.
Conclusion
Today we fast not to starve our flesh or punish our physical bodies, beating them into submission to our own self-righteousness or as vain attempt to impress God. We also do not fast as a "hunger strike" in order to coerce God into action. We fast to allow God to expand our spirit man, our innermost being, the bowels of our belly so that our soul will have a strong enough spirit to defeat the flesh and bring him or herself into alignment with the will of God. We focus not on the needs of the flesh, but of those of the spirit by feeding ourselves spiritual food, for truly as Jesus said, “man shall not live by bread alone, but by every word (rhema) that proceeds out of the mouth of God.”
We fast to expand our spiritual capacity for a transformational God in our lives—whether you call His residence your heart or your belly, your kardia or your koilia. Either way what you mean to say is leb or lebab—the center, most inward part, the seat of all physical, emotional, mental and spiritual life. Fasting is a key spiritual discipline and is not optional, is not extra credit and is not for special occasions—it is intrinsic to the Christian walk. If the Son of God needed to fast on a regular basis to ensure His spirit man was always aligned with the will of the Father, then it is all the more critical for us as flawed, defiant, and self-willed sons and daughters.