A Complete Bible Study on Fasting

Fasting shows up in the Bible at serious moments: grief, confessed sin, danger, and seasons when someone needs clear direction from the Lord. But the same practice can go bad fast when it turns into religious performance. Our primary passage is Matthew 6:16-18, where Jesus assumes His disciples will fast, but He corrects the motive, the method, and the audience.

Jesus sets the rules

Matthew 6 sits inside the Sermon on the Mount. Jesus is describing what true righteousness looks like in His kingdom, and He keeps putting His finger on the same issue: doing religious things to be noticed by people. In this chapter He applies that to giving, praying, and then fasting. He treats fasting as a real part of devotion, but He refuses to let it become a public show.

When not if

One thing many people skim past is the way Jesus words it. He does not speak as if fasting is a rare stunt. He speaks as if there will be times when His disciples fast. That does not mean every believer must fast on a schedule, and it does not mean fasting makes you more saved. Salvation is by grace through faith in Jesus Christ alone. But it does mean Jesus expects His people to use fasting sometimes as a tool for focused seeking.

"Moreover, when you fast, do not be like the hypocrites, with a sad countenance. For they disfigure their faces that they may appear to men to be fasting. Assuredly, I say to you, they have their reward. But you, when you fast, anoint your head and wash your face, so that you do not appear to men to be fasting, but to your Father who is in the secret place; and your Father who sees in secret will reward you openly. (Matthew 6:16-18)

In these verses Jesus contrasts two kinds of fasting. One is done for an audience. The other is done for the Father. The hypocritical kind is designed to be noticed. The true kind is intentionally quiet. Jesus is not mainly teaching about food. He is teaching about the heart.

What hypocrites want

Jesus describes people who make their fasting obvious. In that culture, fasting was often connected with mourning and repentance, so a gloomy look could signal I am really spiritual right now. Jesus says they disfigure their faces, meaning they neglect normal appearance so the fast is visible. They want other people to read their face like a signboard.

Jesus calls that hypocrisy because it looks Godward but it is actually manward. The outside says devotion. The inside says notice me. And Jesus adds a blunt line: they have their reward already. He is not being cute. He is giving a sober diagnosis. If the reward they were after was human approval, then human approval is all they will ever get out of it.

There is also a small wording detail here. The word translated reward carries the idea of payment or wages. It fits the point: they did it for public approval, and public approval is their pay. There is no extra spiritual payout coming later, because the whole act was aimed at the wrong audience.

What the Father wants

Jesus tells His disciples to fast in a way that does not advertise itself. He mentions ordinary grooming. In a first-century Jewish setting, anointing your head with oil was normal personal care, not luxury. The idea is simple: do not turn your fast into a billboard.

Jesus repeats the Father who sees in secret. This is about integrity. God is not fooled by religious theater, but He does see real devotion that nobody else sees. That should steady you in two ways. It comforts you because the Father sees unseen obedience. It corrects you because the desire to be seen can creep into almost anything, even something as serious as fasting.

Old Testament examples

Once Jesus gives the framework, it helps to trace fasting through Scripture with the same question in mind: is this God-facing humility, or is it a religious lever? The Old Testament gives clear snapshots. You see fasting tied to grief, repentance, crisis, and seeking guidance. You also see the Lord reject fasting that stays on the surface.

First mention posture

The first explicit mention of fasting as a spiritual act shows up in a national crisis. Israel had gone to war against Benjamin and suffered defeat. Their response is not just tactical. They go to the house of God, they weep, they sit before the Lord, they fast, and they offer sacrifices.

Then all the children of Israel, that is, all the people, went up and came to the house of God and wept. They sat there before the LORD and fasted that day until evening; and they offered burnt offerings and peace offerings before the LORD. (Judges 20:26)

Notice the cluster of actions. They wept, which shows grief and brokenness. They sat before the Lord, which shows waiting and reverence, not frantic manipulation. They offered burnt and peace offerings, which tied their seeking to worship and reconciliation. From the start, fasting is not presented as a hunger contest or a way to strong-arm God. It is a posture of humility while seeking His direction.

It is also worth saying what the verse does not say. It does not promise that fasting guarantees an answer, and it does not teach that fasting replaces obedience. Judges is full of people doing what is right in their own eyes. A fast that leaves self-rule untouched is not biblical fasting. The whole point is coming low before God and seeking Him on His terms.

Afflicting the soul

Leviticus ties national humbling to the Day of Atonement, the most solemn day on Israel’s calendar. The wording is not always the straightforward term for fasting. The command is to afflict their souls. The Hebrew verb behind afflict carries the idea of humbling yourself, bringing yourself low. It is the opposite of strolling into God’s presence casual and self-assured.

"This shall be a statute forever for you: In the seventh month, on the tenth day of the month, you shall afflict your souls, and do no work at all, whether a native of your own country or a stranger who dwells among you. For on that day the priest shall make atonement for you, to cleanse you, that you may be clean from all your sins before the LORD. It is a sabbath of solemn rest for you, and you shall afflict your souls. It is a statute forever. (Leviticus 16:29-31)

In Israel, that afflicting was commonly expressed with fasting and mourning. The point is humility, not hunger. God was not teaching them to punish themselves. He was teaching them to stop acting like sin is small and life can just carry on untouched.

Another background detail helps here: the same passage commands rest from ordinary work. They were not to grind away as if they could work off guilt. They were to stop, bow low, and receive what God provided through the priestly sacrifice. Even in the Old Testament, forgiveness and cleansing were never earned by human effort. God provided the atonement, and the people were called to humble themselves in response.

For us, Jesus has fulfilled what those sacrifices pointed to. His sacrifice is once for all. We do not fast to pay for sin. Jesus paid for sin through His suffering and physical death as the sinless God-man, and He rose again. Fasting, if you practice it, can fit seasons of confession and repentance, but it must not become self-punishment. It is a way to seek the Father with a contrite heart, not a way to settle your own account.

Empty fasting rejected

Isaiah shows how fasting can be outwardly serious and still be rejected by the Lord. The people were fasting while continuing in sin, strife, and oppression. So the Lord calls the whole thing out as empty.

Indeed you fast for strife and debate, And to strike with the fist of wickedness. You will not fast as you do this day, To make your voice heard on high. Is it a fast that I have chosen, A day for a man to afflict his soul? Is it to bow down his head like a bulrush, And to spread out sackcloth and ashes? Would you call this a fast, And an acceptable day to the LORD? (Isaiah 58:4-5)

Isaiah exposes a hard truth: you can skip meals and still be proud, harsh, and self-willed. You can even use fasting as a way to dress up your demands and make them sound spiritual. God refuses to accept that. If fasting is supposed to humble you, but it makes you more argumentative and more controlling, then the abstaining did not bring you closer to God. It just made you hungry while you stayed the same person.

Later in the chapter the Lord describes the kind of fast He approves, and it includes turning from wickedness and dealing rightly with people in need. That does not mean doing good earns forgiveness. Salvation has always been by grace, received by faith. But real repentance has fruit. A heart that is bowing before God does not keep using people and excusing it with religion.

Fasting in practice

With Matthew 6:16-18 out front, the wider Bible helps fasting make sense. It is not a badge. It is not a shortcut. It is a chosen lowering of normal comforts so you can seek the Lord with fewer distractions and with an honest, humble heart. Scripture shows it often showing up in crisis, grief, and spiritual conflict.

Crisis and help

When Judah faced overwhelming danger in Jehoshaphat’s day, the king’s first move was to seek the Lord, and he proclaimed a fast. Notice the order. Fear is mentioned, but fear does not get to drive. He set himself to seek the Lord.

And Jehoshaphat feared, and set himself to seek the LORD, and proclaimed a fast throughout all Judah. (2 Chronicles 20:3)

In the prayer that follows, Jehoshaphat admits weakness and lack of wisdom. He does not dress it up. He says they have no power and they do not know what to do, but their eyes are on God. That kind of honesty is a big part of biblical fasting. Fasting is one bodily way of agreeing with that prayer: I cannot carry this. I need the Lord.

O our God, will You not judge them? For we have no power against this great multitude that is coming against us; nor do we know what to do, but our eyes are upon You." (2 Chronicles 20:12)

The chapter also guards you from another mistake. The fast did not replace obedience and action. God gave direction, and the people obeyed. Fasting supports seeking God so that faithful steps become clearer. It is not a religious way to stall out.

Grief and mourning

Fasting also shows up in grief. After Saul and his sons died, the men of Jabesh Gilead recovered the bodies, honored them in burial, and mourned, including a seven-day fast.

Then they took their bones and buried them under the tamarisk tree at Jabesh, and fasted seven days. (1 Samuel 31:13)

In grief, fasting is not a way to get leverage with God. It is an honest recognition that life is heavy and the soul needs the Lord’s comfort. The seven days also mark time. It is a complete period of mourning. It forces a pause when people are tempted either to deny reality or to rush ahead as if nothing happened.

And sometimes, in grief, eating really does feel out of place. Not because food is wrong, but because sorrow strips life down to what is most important. In that season, fasting can become a simple way to set time aside for prayer, reflection, and quiet dependence. If a full food fast is unwise for your health, you can still practice the heart of it by setting aside another legitimate comfort for focused prayer.

Jesus and temptation

Jesus also shows fasting connected to spiritual conflict. At the beginning of His public ministry, the Spirit led Him into the wilderness to be tempted by the devil, and He fasted forty days.

Then Jesus was led up by the Spirit into the wilderness to be tempted by the devil. And when He had fasted forty days and forty nights, afterward He was hungry. (Matthew 4:1-2)

His hunger shows the temptation was real. The devil aimed at a legitimate physical need and suggested an illegitimate way to meet it. The issue was not bread. The issue was acting independently of the Father’s will. Jesus answered with Scripture from Deuteronomy, showing that God’s Word is more necessary than immediate relief.

But He answered and said, "It is written, "Man shall not live by bread alone, but by every word that proceeds from the mouth of God."' (Matthew 4:4)

Now tie that back to Matthew 6. In Matthew 6, the issue is not hunger either. It is who you are living for. One more Greek word note helps: the word translated hypocrites refers to an actor, someone playing a part. That is why the whole section feels like stage language. A hypocrite is performing religion. Jesus says do not perform fasting. Seek your Father.

Also keep your footing on the gospel. Jesus’ victory over temptation is not mainly a self-help lesson. His obedience shows Him as the spotless Savior, qualified to die for sinners and rise again. You are saved by grace through faith in Him, not by fasting, not by willpower, not by consistency. Then, as His disciple, you can use fasting in a healthy way: as training to say no to the flesh and to answer temptation with what is written.

Here is a plain observation that can help in real life: fasting does not magically make you holy. It tends to reveal what is already running you. If a skipped meal turns you into a mean, sharp person, that is not just low blood sugar. It is often the heart coming to the surface. That is not the end of the world, but it is a moment to get honest with God, confess sin, and ask for real change.

My Final Thoughts

Matthew 6:16-18 keeps fasting from turning into religion-for-show. Jesus assumes His people will fast sometimes, but He demands the right audience and the right motive. Fasting is not a way to force God’s hand, and it is not a badge for spiritual people. It is a quiet, voluntary lowering of normal comforts so you can seek the Father with focus, humility, and a readiness to obey.

If you decide to fast, keep it simple and honest. Tie it to clear prayer: confession of sin, seeking wisdom, intercession in a crisis, or asking for help in temptation. Make sure your relationships and your behavior match your prayers. When the fast is done, let the most important result be obedience to what God has already made clear in His Word.