Fasting may be the most neglected of the historic Christian disciplines. We talk readily about prayer and Bible reading; fasting we mostly skip, or quietly assume belongs to monks and the super-spiritual. Yet it runs all through the Bible — Moses fasted, David fasted, Esther fasted, Daniel fasted, the early church fasted, and Jesus Himself fasted forty days in the wilderness. And He plainly expected His followers to keep doing it. So let me take the mystery out of it and put a practical, biblical tool back in your hands.

First, the plain definition. To fast is to abstain, for a set time and for a spiritual purpose, from something good — usually food. It is the deliberate setting aside of a normal, legitimate appetite in order to give yourself more fully to seeking God. The key words are voluntary, temporary, and spiritual purpose. It is not starving, not a stunt, and not magic.

Jesus assumed His followers would fast

In the Sermon on the Mount, Jesus put fasting right alongside giving and praying as a normal part of the devout life — and notice the word He used:

Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward. But thou, when thou fastest, anoint thine head, and wash thy face; That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly. Matthew 6:16–18

He says when ye fast, not if — the same way He says “when ye pray.” Fasting was assumed. But look at the warning, because it is the whole danger of the discipline: the hypocrites fasted to be seen fasting, advertising their piety with gloomy faces. Jesus says that performance is its own and only reward. True fasting is hidden — done for the Father “which is in secret,” not for an audience. So the first rule of fasting is: tell no one who doesn’t need to know. The moment you fast to be admired, you have traded God’s reward for a cheaper one. Once asked why His disciples didn’t fast like others, Jesus explained that they would — once He, the bridegroom, was taken from them (Matthew 9:15). We live in exactly that season: the time of joyful longing for our absent Lord, and fasting is one way we express it.

Why Christians fast

So what is fasting actually for? Several things, woven together. We fast to seek God more earnestly — to humble ourselves and concentrate our prayers in seasons when we desperately need His help, guidance, or deliverance. Joel called a whole nation to it:

Therefore also now, saith the LORD, turn ye even to me with all your heart, and with fasting, and with weeping, and with mourning: Joel 2:12

We fast to express repentance and humility, turning to God “with all your heart.” We fast to seek guidance for big decisions — the early church fasted and prayed before sending out missionaries and appointing leaders:

As they ministered to the Lord, and fasted, the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them. And when they had fasted and prayed, and laid their hands on them, they sent them away. Acts 13:2–3

And above all, we fast to feast on God. This is the deepest purpose. When you feel the hunger pangs, you turn them into a prayer: “Lord, I am hungry — and I am hungrier still for You.” Fasting takes the body’s loudest appetite and harnesses it to declare that God is more necessary than food. It is a way of saying, with your stomach and not just your lips, what Jesus said in that same wilderness: man shall not live by bread alone, but by every word that proceedeth out of the mouth of God.

The heart God is looking for

Here is the warning the prophets sounded again and again: God is not impressed by fasting that leaves the heart unchanged. The people in Isaiah’s day fasted and then complained that God hadn’t noticed — while they oppressed their workers and ignored the poor. God’s answer redefined the whole thing:

Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke? Isaiah 58:6

The fast God chooses is not merely an empty stomach but a softened, justice-loving, generous heart. Fasting that does not make you more humble, more prayerful, more merciful, and more attentive to the people God loves has missed the point entirely. Skipping lunch while harboring a grudge accomplishes nothing. So as you fast, let the discipline do its work on your character — let hunger make you tender rather than irritable, and channel the time and even the money you would have spent on food toward prayer and toward the needs of others.

How to fast: a practical start

If you have never fasted, here is gentle, practical counsel to begin well. Start small. You do not need to attempt forty days. Skip one or two meals, or fast from one sunrise to the next, and give the time you would have spent eating to prayer and Scripture. Pair it with prayer. Fasting without prayer is just going hungry; the whole point is to seek God, so plan to use the hunger as a prompt to turn to Him throughout the day. Pick a clear focus. Fast about something specific — a decision, a burden, a person, a season of repentance — so the discipline has direction. Be wise about your body. Drink water, and if you have a medical condition, are pregnant, are diabetic, or have any history of an eating disorder, talk to a doctor first and consider fasting from something other than food — media, entertainment, a habit — which can serve the same spiritual purpose. God wants your heart, not your harm. And keep it quiet. Remember the secret-place principle: this is between you and your Father.

Done in this spirit, fasting becomes one of the most clarifying things in the Christian life. It exposes how much we are ruled by our appetites, and it trains us to find our deepest satisfaction in God Himself. Pair it with the daily disciplines I describe in How to Pray and How to Read the Bible, and you have the ordinary, time-tested means by which God grows His people. The next time you face a decision too big for you, a sin too stubborn for you, or simply a hunger for more of God than your routine has been giving you — consider pushing the plate away for a while, and feasting instead on Him.