What is fasting?

Question 11002.

Biblical fasting is the deliberate setting aside of food, for a set time, in order to give undivided attention to God. That is the whole of it, and everything else people attach to the practice is either application or invention.

It is one of the least discussed and most misunderstood habits in Christian life. Some treat it as a spiritual lever that forces God’s hand. Others quietly assume it belonged to an older, hungrier era of the Church and can safely be left there. Neither view survives an honest look at Scripture.

What biblical fasting actually is

The Hebrew verb is tsum, and the Greek is nesteuo, both of which mean quite simply to abstain from food. There is nothing mystical in the vocabulary. The significance lies in what the abstaining is for.

In Scripture, biblical fasting always accompanies something else. It goes with mourning, as when David fasted over his dying child. It goes with repentance, as at Nineveh. It goes with urgent intercession, as when Esther called Israel to fast before she approached the king. It goes with seeking direction, as when the church at Antioch fasted before sending Barnabas and Saul (Acts 13:2-3). Fasting is never the point; it clears the ground so that the point can be attended to.

That is why biblical fasting is not a hunger strike. We are not withholding lunch until God relents. We are removing a good and lawful comfort so that our appetite for God is not permanently drowned out by our appetite for everything else.

Did Jesus expect us to fast?

He did, and He said so without fuss. In the Sermon on the Mount He said ‘when you fast’, not ‘if you fast’ (Matthew 6:16-18), placing it alongside giving and praying as an assumed part of ordinary discipleship.

When the disciples of John asked why His followers did not fast, Jesus answered that the wedding guests do not mourn while the bridegroom is with them, but the days will come when the bridegroom is taken away, and then they will fast (Matthew 9:14-15). Those days are the days we are living in. The bridegroom has gone to prepare a place, and the Church waits.

So the New Testament neither commands biblical fasting as a legal requirement nor abolishes it. It assumes it, the way it assumes that believers will give and pray, and it leaves the frequency to conscience.

The way God rejects fasting

There is a kind of fasting God will not have. Isaiah records His complaint against people who fasted while oppressing their workers and quarrelling with their neighbours, and asks whether that is the fast He has chosen (Isaiah 58:3-7). The fast He wants looses the bonds of wickedness and shares bread with the hungry.

Jesus makes the same point from a different angle. The hypocrites disfigure their faces so that their fasting will be noticed, and the notice is all the reward they get. Wash your face, He says, and let it be between you and your Father.

This is worth saying plainly because biblical fasting is unusually vulnerable to pride. Nothing feels more spiritual than going without, and nothing is easier to mention casually in conversation. If you find yourself hoping someone will ask why you are not eating, the fast has already done its worst work rather than its best.

The different shapes a fast can take

Scripture shows several patterns. There is the ordinary fast, going without food while continuing to drink, which is what Jesus did for forty days in the wilderness before Luke notes that afterwards He was hungry (Luke 4:2). There is the partial fast, as when Daniel took no delicacies, meat or wine for three weeks (Daniel 10:2-3). There is the absolute fast without water, which appears rarely and only ever briefly, as with Esther’s three days and Paul’s blindness at Damascus.

Length is not a measure of spiritual seriousness. The forty-day fasts of Moses, Elijah and Jesus stand at the head of redemptive history and are not offered to us as targets. Most of the fasting in Scripture lasted a day, and a day given honestly to God is worth more than a week endured for the sake of the record.

Married believers should also weigh Paul’s principle in 1 Corinthians 7:5, where he allows a couple to abstain from one another by agreement for a limited time in order to devote themselves to prayer, and then tells them to come back together. Biblical fasting is never meant to be a unilateral withdrawal that leaves someone else carrying the cost of your devotion.

There is a wider application too. Going without television, social media, spending or sleep is not fasting in the strict biblical sense, since the vocabulary of biblical fasting is tied to food. But the underlying logic transfers honestly enough. Anything that has grown loud enough to drown out prayer can be set aside for a season with real profit.

What fasting does and does not achieve

Biblical fasting does not earn anything. It does not make God more willing, more attentive, or more inclined to say yes. Our standing with Him rests on what Jesus did, and no amount of skipped meals adds to a finished work.

What it does is expose us. Take away food for a day and you quickly discover how much of your emotional weather is regulated by comfort, how impatient you are, how thin your reserves of grace towards other people run when your blood sugar dips. That exposure is a mercy, because you cannot repent of what you have not noticed.

It also sharpens attention. The hours you would have spent eating become hours available for prayer, and the physical emptiness keeps returning your mind to the reason you are empty. That is the mechanism, and it is a fairly humble one. Fasting concentrates the mind on God rather than manipulating the will of God.

How to begin without doing damage

Start small. One meal, then a day, and only then anything longer. Drink water. If you have any condition affected by food, diabetes above all, or a history of disordered eating, or you are pregnant or nursing, speak to your doctor first and consider fasting from something other than food. There is no virtue in harming a body the Spirit indwells.

Decide in advance what the time is for. A fast with no purpose becomes a diet with a religious label. Choose the matter you are bringing to God, whether a decision, a person, a besetting sin or a season of dryness, and give the hours to prayer and Scripture rather than to distraction.

Keep it quiet. Tell your household if the practicalities require it, and otherwise say nothing. And do not be surprised if the first attempt feels like nothing at all. Most worthwhile habits are unremarkable at the start.

Fasting in the life of a church

Corporate fasting appears throughout Scripture, from Israel gathering at Mizpah to the leaders at Antioch seeking direction before a missionary journey. There is something right about a congregation facing a weighty decision and choosing to seek God together rather than trusting its own committee work.

I would rather see this offered than imposed. A church that requires biblical fasting has manufactured a law the New Testament did not give, and the results will be resentment dressed as devotion. A church that quietly invites people to set aside a day before a significant decision is doing something closer to the apostolic pattern.

Where fasting has gone wrong in modern church life, it has usually been tied to prosperity teaching, promising breakthrough or financial return in exchange for the discipline. That is a transaction, not a fast, and it treats God as a mechanism. Real dependence on the Spirit looks nothing like that, as I have argued when writing about how the Spirit guides.

So, now what?

If you have never fasted, pick a day in the next fortnight, choose one meal, and give the time to God with something specific to pray about. That is a beginning small enough to actually happen.

If you have fasted for years, ask whether it has quietly become a performance, either for others or for yourself. Biblical fasting that leaves you pleased with yourself has taken you further from God than the sandwich would have done.

And if you are hesitant, notice that the question is not really about food. It is about whether there is anything in your life you would willingly go without in order to pay attention to God. What would you name, and what has been stopping you from naming it for the past year or so?

And when you fast, do not look gloomy like the hypocrites, for they disfigure their faces that their fasting may be seen by others. Truly, I say to you, they have received their reward.

Matthew 6:16, ESV