Short answer: Matthew 6:16–18 assumes that followers of Jesus will fast, but it never gives a frequency, a calendar, or a minimum. Jesus instead contrasts fasting done to be seen by people with fasting directed to the Father who sees in secret. So the passage answers the question of how often by declining to answer it, and by redirecting us to motive, secrecy, and trust in the Father's reward. Any teaching that makes one schedule a rule for every Christian goes beyond what this text says.
Where Jesus places fasting in the sermon on the mount
Matthew 6:16–18 sits inside the Sermon on the Mount, Jesus' extended teaching to his disciples about life under God's reign. Within that sermon he treats three practices of devotion in a row: giving, praying, and now fasting. The shape is instruction for listening disciples, built on a repeated contrast between what hypocrites do and what his followers are to do. The hypocrites wear sad faces and disfigure themselves so others will notice their fasting. Jesus says they have received their reward. His disciples are told to anoint the head and wash the face, so the fasting is not seen by people but by the Father who sees in secret.
The placement matters. Verses 14–15 on forgiving others come immediately before, and verses 19–20 on treasures on earth come immediately after. A single contrast governs the whole stretch: practice aimed at human notice has its reward already, while practice aimed at the Father is seen and answered by him. The setting is Jewish devotion, where fasting was a recognized practice. Jesus neither abolishes it nor turns it into a fixed rule with a required frequency. He assumes it will happen, saying when you fast, and then addresses the heart behind it rather than the calendar.
The nearby theme of reward and treasure keeps fasting from becoming a technique for earning anything from God. The Father who sees in secret is the one who rewards, and that promise rests on his grace, not on the length or severity of our abstinence. This passage tells us how fasting is to be done, quietly before God, not how often. Readers with medical conditions, a history of disordered eating, or who are pregnant should seek appropriate medical advice before fasting, and no one should treat fasting as a way to earn God's favor or force a desired outcome.
When you fast: what Jesus actually said
The section opens with a small word that carries a lot of weight. Jesus says when you fast, not if you fast. He is not debating whether his people will fast; he assumes they will, the same way he assumes they will give and pray in the verses just before this. The question he answers is not whether but how. Notice also that he does not scold fasting itself. He corrects a way of fasting, which means the practice is assumed and only its direction is at stake. That is worth sitting with before we ask how often.
The problem Jesus names is display. He describes people who make their faces look miserable so that others will notice the discipline. The word he uses for them is hypocrites, and here it means religious acts performed for an audience. The phrase that they may be seen by men to be fasting pins down the exact failure: the fast is aimed at observers. His alternative is almost comically ordinary. Anoint your head, wash your face, look normal. Do not arrange your appearance to advertise hunger. Fasting is meant to be invisible to everyone but God.
Then Jesus locates both the audience and the reward. Your Father sees in secret, and your Father who sees in secret will reward you. The gaze moves from the crowd to the Father, and so does the payoff. This is not a technique for extracting anything from God; it is a trust that he sees what no one else sees. Two cautions belong here. Fasting does not earn God's favor or force an outcome, and readers who are pregnant, living with a medical condition, or carrying a history of disordered eating should get proper medical advice before they fast at all.
But if you don’t forgive men their trespasses, neither will your Father forgive your trespasses.
Fasting before the Father who sees in secret
Jesus does not begin this teaching by arguing that his followers should fast. He begins with the word when. The assumption is that fasting is part of devoted life, the way prayer and giving are. What he addresses is not whether or how often, but how: not with sad faces and disfigured features meant to be noticed, but with a washed face and anointed head, ordinary and unremarkable to onlookers. The hypocrites in view are not people who fast too much; they are people who fast for an audience. Jesus says they have received their reward, meaning the notice they wanted is the whole payment. No calendar, no minimum, no required season appears here.
The verses on either side hold this teaching in place. Just before, Jesus ties the Father's forgiveness to our forgiving others, so the reader comes to this passage already warned that religious practice and a hardened heart can coexist. Just after, he turns to treasure, warning that earth's stores are consumed and stolen while heaven's are not. Read together, the section makes one point: practice aimed at human notice is paid in full here, while practice aimed at the Father is seen by him. That is why fasting cannot be a technique for earning anything. The reward Jesus describes is the Father's own seeing and answering, not a lever we pull.
So the honest answer to how often a Christian should fast is that this passage gives no number, and any teaching that turns a schedule into a rule for all believers goes beyond the text. Jesus redirects the question from frequency to direction: is this done for the Father who is in secret, or for the people who might notice? That leaves room for ordinary, unhurried fasting without display. It also means fasting is never a way to earn God's favor or force an outcome. Readers with medical conditions, a history of disordered eating, or who are pregnant should seek appropriate medical advice before fasting.
What Jesus does and does not command about fasting
Jesus begins with a word that assumes the practice: when you fast, not if you happen to. He then spends the bulk of the passage not on the act itself but on its visibility. The hypocrites disfigure their faces so that others will notice. Jesus tells his disciples to anoint the head and wash the face, the ordinary grooming of a normal day, so that no one can tell they are fasting. The command here is about motive and secrecy, not about frequency. Careful readers notice what is absent: no day is named, no season is set, and no number of meals is given. The text regulates how fasting is done, not how often.
Evangelical readers agree on that much and then part ways. Some read the assumed practice, together with the fasting recorded in Acts, as a pattern the church should keep regularly, and they build disciplines around it. Others point out that the New Testament contains no command to fast, no fixed day, and no required season, so they treat it as a voluntary practice that no one may impose. Traditions that observe set seasons such as Lent and traditions that deliberately avoid calendars both appeal to this passage. The disagreement is real, and it is not resolved by the verses themselves. What stays central is that fasting is directed to God, hidden from people, and never used to manipulate him.
The reward Jesus promises is also read two ways. Some hear a present sense of the Father who sees in secret drawing near; others hear the final reward of the resurrection. The text does not specify, and it does not guarantee a particular outcome, emotional relief, or an answer to prayer. What it does say is that the Father sees what is hidden. That is the limit and the comfort. Fasting is not a lever and not a way to earn favor; grace comes first, and our response is hidden before God. Anyone with a medical condition, a history of disordered eating, or who is pregnant should seek medical advice before fasting.
The passage closes the door on display and leaves the calendar open. Jesus says nothing about how often, which days, or how long. He says a great deal about who is watching. The one who sees in secret is the audience, and that single focus settles the motive while leaving the schedule to wisdom and liberty.
Fasting before the Father who sees in secret
Jesus has just taught his disciples to pray, and he keeps going with fasting as though it were the ordinary companion of prayer and giving. Notice what he assumes: when you fast, not if you feel like it. The problem he names is not the practice but the theater around it. The hypocrites disfigure their faces so people will notice. Jesus says they have their reward already, meaning the attention they wanted is the whole payment. The kingdom practice is different. Anoint your head, wash your face, look normal. Fasting is directed to a Father, not to an audience, and Jesus describes that Father as one who sees in secret.
The phrase that carries the passage is the Father who sees in secret. That is where the gospel enters without being forced. Fasting does not purchase standing with God; it is the response of someone already seen and known by him. Jesus speaks as the one who defines life in his kingdom, and he places fasting among the quiet practices of a child before a Father. Nothing in the act earns the reward; the reward comes from the Father's seeing, not from our display. This is why hiddenness is possible at all. A person who is already accepted can fast without needing anyone to notice, because the Father's attention is enough.
Jesus ends by pointing to treasure in heaven, where nothing is consumed or stolen. Fasting loosens our grip on earthly comfort, and the gospel supplies the treasure that makes that loosening reasonable. It is the response of someone who already has a Father, not a transaction to secure one. So frequency is not the measure here; direction is. Readers with medical conditions, a history of disordered eating, or who are pregnant should seek appropriate medical advice before fasting, and no one should treat fasting as a way to earn God's favor or force a desired outcome.
What faithful fasting looks like in ordinary life
Matthew 6:16–18 gives no frequency, no calendar and no minimum. Jesus says "when you fast," not how often, and the rest of the passage concerns the manner, not the schedule. That silence is itself instruction. Timing is left to wise judgment, circumstances and a real desire for God rather than to a rule that binds the conscience. A Christian may set aside a day, a season, or a turning point such as a decision or a grief, and may also go without fasting for a time without guilt. What the passage does insist on is that the fasting stay between the person and the Father.
The concrete picture here is quietness. The hypocrites disfigure their faces so others will notice, and Jesus says they have their reward already. His alternative is ordinary: wash your face, anoint your head, appear normal, and let the Father who sees in secret be the one who knows. That rules out the miserable expression, the casual mention, the spiritual resume. Fasting belongs with prayer, and it belongs beside the plain duties of love, not in place of them. It is never a lever that obliges God to give a particular answer, because the Father is not a machine to be moved by going without food.
Grace is the ground of all this. The Father already sees and already knows, so fasting is not the price of acceptance but the response of a child who is already accepted. That is why no one should fast to earn God's favor or to force an outcome. Readers who are pregnant, living with a medical condition, or who have a history of disordered eating should seek appropriate medical advice before fasting. The passage leaves the calendar open and closes the door on display, and that is enough to shape an ordinary, unhurried obedience.
Biblical fidelity check
Read slowly, Matthew 6:16–18 sits inside Jesus' teaching on hidden devotion, right after his words on forgiveness and just before his warning about earthly treasure. The risk here is turning a description of hypocrites into a checklist about appearances, or lifting "when you fast" into a schedule Jesus never gives. Notice the opening word: he says when, not if, treating fasting as expected among his people. The problem named is not fasting but fasting done so that others notice. "Anoint your head, and wash your face" simply means look ordinary. The audience and the reward both belong to the Father who sees in secret.
Evangelical readers agree Jesus expects fasting and forbids display, yet they differ on how far this binds the church. Some read "when you fast" as establishing a continuing practice and point to fasting in Acts; others observe that no command, day, or frequency appears anywhere in the New Testament, so they treat fasting as voluntary. Traditions differ over set seasons such as Lent, and readers differ on whether the reward is present nearness or final resurrection. What stays central is that fasting is directed to God, kept free of display, and never used to manipulate him. The text commands secrecy and motive, and commands no schedule.
Reading Matthew 6:16-18 alongside other passages
For further study, consider Jesus Denounces Hypocrisy in Matthew 23 on fasting in the Old Testament, Matthew 1: Genealogy and Birth of Jesus on Jesus' own forty days in the wilderness, Matthew 10: Jesus Sends the Twelve with Authority on the early church's fasting in Acts, and Matthew 12: Lord of the Sabbath and Sign of Jonah on how motive shapes religious practice in the Sermon on the Mount.
Frequently asked questions
Does the Bible command Christians to fast, or is it voluntary?
In this passage Jesus does not command fasting; he assumes it will happen among his disciples and regulates how they do it. He begins with "when you fast," not: if you fast, and instructs them to anoint the head and wash the face rather than put on a sad face to be noticed. So fasting here is expected practice, but its timing and frequency are left voluntary, while its motive is not: it is directed to the Father who sees in secret, not to spectators.
How can I fast in a way that other people do not notice, the way Jesus tells his followers to?
Jesus answers this by telling you to keep your fasting ordinary on the outside: wash your face and go about looking as you normally do, so that no one can tell from your appearance that you are fasting (6:17–18). The point is not secrecy for its own sake but direction: your fasting is meant to be seen by your Father who is in secret, not performed for an audience of people. The hypocrites in this passage fast in order to be noticed, and Jesus says their public attention is the whole of their reward. Fast before God rather than before others, and leave the reward to him.
When I fast without making it visible to others, what reward does Jesus say the Father gives?
Jesus promises that your Father, who sees in secret, will reward you, but he does not name what that reward is. The contrast in 6:16–18 is between people who fast to be seen by others and receive their reward already, and a person who fasts unseen before God. The reward is left in the Father's hands, so the passage gives assurance of reward without specifying its content or timing. What stays central is fasting directed toward God rather than toward an audience.
