Sermon on the Mount: Fasting

What is fasting? Why, how, and when should we fast?

Written by David Steltz on .



We continue in Matthew today, we’re in the sermon on the hill, right in the middle of the sermon, chapter 6, and for the past few weeks we’ve been in a section of the sermon where Jesus is addressing the way his followers ought to “practice righteousness,” that is practice “spiritual disciplines,” or as Mike put it last week, how we “live out our faith” or how we “live for God.” This idea of intentionally doing things, specific actions and practices which are performed with the intention of pleasing God and becoming more like him.

And there’s this assumption that Jesus’s followers DO already have this desire to “practice righteousness” but there’s a question of HOW, the methods of doing so, which really boils down to their motives of doing so. And overall, the point Jesus is making is, no matter what it is you’re doing, don’t do it for the purpose of drawing attention to yourself, so that other people look at you and think “wow, that person is so righteous!”

And remember, it’s not that we need to HIDE our righteousness, our faith, our good works, just in the last chapter Jesus said to let your good works be known, to be a light on a hill! BUT, now he’s saying NOT to do it like the hypocrites, the actors, who do good things on the outside, but who are really hiding behind a mask, on a stage, doing it for their own benefit and their own glory rather than out of love for God and love for those around them. 

Whether it’s giving to the poor, or praying to God, or fasting, it should be done quietly and humbly, not loudly and proudly.

It’s that 3rd example of “practicing righteousness” that we’ve come to today, this idea of “fasting.” We’re going to explore this concept together.

Main Passage

First of all, let’s refresh our memories by reading what Jesus says here in Matthew six:

Matthew 6:16–18 CSB
16 “Whenever you fast, don’t be gloomy like the hypocrites. For they make their faces unattractive so that their fasting is obvious to people. Truly I tell you, they have their reward. 17 But when you fast, put oil on your head and wash your face, 18 so that your fasting isn’t obvious to others but to your Father who is in secret. And your Father who sees in secret will reward you.

Again, the assumption is that Jesus’s followers WERE fasting, the only question was HOW they fasted.

So, what exactly is fasting, and what was the significance of this spiritual discipline to Jesus and his followers?

First, let me ask: what does fasting mean to you?

WHY would someone fast?

Have you ever been a part of a church that had a regular practice of fasting?

What is fasting?

Here’s a Bible dictionary definition of the word fasting:

A ritual of abstaining from food and/or drink for a predetermined period; practiced in the Bible primarily as a means of mourning. Fasting frequently occurs in the Old Testament in response to suffering or disaster, in conjunction with other mourning rituals.

This type of ritual was common in Israel, and also throughout the rest of the ancient near east. It was a display of humility and grief, often just as public and social as a feast would be, but for the opposite purpose. A feast shows off wealth and prosperity, a fast displays weakness and neediness. 

Fasting is the opposite of feasting, and as feasting was associated with celebration and merriment, so fasting was associated with mourning, sobriety, and piety.

Fasting in the Old Testament

In the old testament, we see fasting often accompanied by sackcloth and ashes, two other ritualistic, symbolic elements of grief and piety:

Fasting to Mourn

After hearing about Saul and Jonathan’s death:

1 Samuel 31:9–13 CSB
9 They cut off Saul’s head, stripped off his armor, and sent messengers throughout the land of the Philistines to spread the good news in the temples of their idols and among the people. 10 Then they put his armor in the temple of the Ashtoreths and hung his body on the wall of Beth-shan. 11 When the residents of Jabesh-gilead heard what the Philistines had done to Saul, 12 all their brave men set out, journeyed all night, and retrieved the body of Saul and the bodies of his sons from the wall of Beth-shan. When they arrived at Jabesh, they burned the bodies there. 13 Afterward, they took their bones and buried them under the tamarisk tree in Jabesh and fasted seven days.

Even David, who Saul considered an enemy, and was trying to kill, had the same response:

2 Samuel 1:11–12 CSB
11 Then David took hold of his clothes and tore them, and all the men with him did the same. 12 They mourned, wept, and fasted until the evening for those who died by the sword—for Saul, his son Jonathan, the Lord’s people, and the house of Israel.

Fasting in the Law

There are no laws which directly command fasting, using the Hebrew word for fast (צוֹם, tsom), however there is ONE command, related to the Day of Atonement, which commands the people to “deny themselves,” which is a parallel concept to fasting, though may extend beyond simply denying yourself food, but other physical needs and pleasures, temporarily:

​Leviticus 23:26–32 CSB
26 The Lord again spoke to Moses: 27 “The tenth day of this seventh month is the Day of Atonement. You are to hold a sacred assembly and practice self-denial; you are to present a food offering to the Lord. 28 On this particular day you are not to do any work, for it is a Day of Atonement to make atonement for yourselves before the Lord your God. 29 If any person does not practice self-denial on this particular day, he is to be cut off from his people. 30 I will destroy among his people anyone who does any work on this same day. 31 You are not to do any work. This is a permanent statute throughout your generations wherever you live. 32 It will be a Sabbath of complete rest for you, and you must practice self-denial. You are to observe your Sabbath from the evening of the ninth day of the month until the following evening.”

So, in this case it coincides with the Sabbath rest, and takes it a step further, in correlation with this concept of repentance and atonement, the act of confession, repentance, and making reparations for their sin.

Fasting to Repent

We can see fasting used as a symbol of repentance in other circumstances too:

After being confronted by the prophet Samuel (after Judges, before David and Solomon):

1 Samuel 7:6 CSB
6 When they gathered at Mizpah, they drew water and poured it out in the Lord’s presence. They fasted that day, and there they confessed, “We have sinned against the Lord.” And Samuel judged the Israelites at Mizpah.

Nineveh, after being confronted by Jonah ( after David and Solomon, before the exile):

Jonah 3:4–9 CSB
4 Jonah set out on the first day of his walk in the city and proclaimed, “In forty days Nineveh will be demolished!” 5 Then the people of Nineveh believed God. They proclaimed a fast and dressed in sackcloth—from the greatest of them to the least. 6 When word reached the king of Nineveh, he got up from his throne, took off his royal robe, covered himself with sackcloth, and sat in ashes. 7 Then he issued a decree in Nineveh: By order of the king and his nobles: No person or animal, herd or flock, is to taste anything at all. They must not eat or drink water. 8 Furthermore, both people and animals must be covered with sackcloth, and everyone must call out earnestly to God. Each must turn from his evil ways and from his wrongdoing. 9 Who knows? God may turn and relent; he may turn from his burning anger so that we will not perish.

After hearing Ezra read from the law (after the exile):

Nehemiah 9:1–2 CSB
1 On the twenty-fourth day of this month the Israelites assembled; they were fasting, wearing sackcloth, and had put dust on their heads. 2 Those of Israelite descent separated themselves from all foreigners, and they stood and confessed their sins and the iniquities of their ancestors.

Fasting as a Response to Danger

Fasting is also used, not just in response to death, but in the anticipation or possibility of death, or of defeat, almost like an attempt to preemptively seek protection against that which might ultimately give a cause to mourn, before it has happened:

When the Israelite army is losing a fight against the tribe of Benjamin (The tribe of Benjamin had committed horrible atrocities, and Yahweh told Israel to fight against them):

​Judges 20:26 CSB
26 The whole Israelite army went to Bethel where they wept and sat before the Lord. They fasted that day until evening and offered burnt offerings and fellowship offerings to the Lord.

In this case, not only were they fasting because they were being defeated, they were also asking God for guidance, saying “God, are you sure we’re doing the right thing? Should we continue to fight against our brother tribe?” God responds and says “yes, you’ll be victorious tomorrow.” And the next day:

Judges 20:35 CSB
35 The Lord defeated Benjamin in the presence of Israel, and on that day the Israelites slaughtered 25,100 men of Benjamin; all were armed.

When Jehoshaphat is faced with the Moabite and Ammonite armies:

​2 Chronicles 20:1–3 CSB
1 After this, the Moabites and Ammonites, together with some of the Meunites, came to fight against Jehoshaphat. 2 People came and told Jehoshaphat, “A vast number from beyond the Dead Sea and from Edom has come to fight against you; they are already in Hazazon-tamar” (that is, En-gedi). 3 Jehoshaphat was afraid, and he resolved to seek the Lord. Then he proclaimed a fast for all Judah,

Soon thereafter:

​2 Chronicles 20:22 CSB
22 The moment they began their shouts and praises, the Lord set an ambush against the Ammonites, Moabites, and the inhabitants of Mount Seir who came to fight against Judah, and they were defeated.

In preparation for a potentially perilous journey, seeking God’s protection instead of the king’s:

​Ezra 8:21–23 CSB
21 I proclaimed a fast by the Ahava River, so that we might humble ourselves before our God and ask him for a safe journey for us, our dependents, and all our possessions. 22 I did this because I was ashamed to ask the king for infantry and cavalry to protect us from enemies during the journey, since we had told him, “The hand of our God is gracious to all who seek him, but his fierce anger is against all who abandon him.” 23 So we fasted and pleaded with our God about this, and he was receptive to our prayer.

When Nehemiah hears the gates of Jerusalem have been destroyed and the people are in danger:

​Nehemiah 1:1–4 CSB
1 The words of Nehemiah son of Hacaliah: During the month of Chislev in the twentieth year, when I was in the fortress city of Susa, 2 Hanani, one of my brothers, arrived with men from Judah, and I questioned them about Jerusalem and the Jewish remnant that had survived the exile. 3 They said to me, “The remnant in the province, who survived the exile, are in great trouble and disgrace. Jerusalem’s wall has been broken down, and its gates have been burned.” 4 When I heard these words, I sat down and wept. I mourned for a number of days, fasting and praying before the God of the heavens.

After hearing about Haman’s plot to kill the Jews in exile:

Esther 4:1–3 CSB
1 When Mordecai learned all that had occurred, he tore his clothes, put on sackcloth and ashes, went into the middle of the city, and cried loudly and bitterly. 2 He went only as far as the King’s Gate, since the law prohibited anyone wearing sackcloth from entering the King’s Gate. 3 There was great mourning among the Jewish people in every province where the king’s command and edict reached. They fasted, wept, and lamented, and many lay in sackcloth and ashes.

And again, before Esther approaches the king uninvited, she proclaims a fast for all the Jews in the city:

​Esther 4:16 CSB
16 “Go and assemble all the Jews who can be found in Susa and fast for me. Don’t eat or drink for three days, night or day. I and my female servants will also fast in the same way. After that, I will go to the king even if it is against the law. If I perish, I perish.”

The prophet Joel tells his audience to fast and lament the future day of destruction when talking about the day of the Lord, so here fasting is even seen in connection with something which was not necessarily imminent, but serious nonetheless:

Joel 1:13–15 CSB
13 Dress in sackcloth and lament, you priests; wail, you ministers of the altar. Come and spend the night in sackcloth, you ministers of my God, because grain and drink offerings are withheld from the house of your God. 14 Announce a sacred fast; proclaim a solemn assembly! Gather the elders and all the residents of the land at the house of the Lord your God, and cry out to the Lord. 15 Woe because of that day! For the day of the Lord is near and will come as devastation from the Almighty.

Fasting to Intensify Prayer

Whether expressing grief, or fear, or repentance, or some specific need, fasting is often practiced alongside prayer in the Old Testament, as a way of demonstrating the intensity and genuineness, the authenticity and intimacy of the prayer. This is the case with the Israelites seeking guidance when fighting against Benjamin, it’s the case with Esther, Ezra, and Nehemiah. Here are a couple more:

From Psalms, associating fasting with the genuineness of prayer:

​Psalm 35:13 CSB
13 Yet when they were sick, 
my clothing was sackcloth; 
I humbled myself with fasting, 
and my prayer was genuine.

And even though prayer isn’t always explicitly mentioned as accompanying fasting, they are so often mentioned together, that even in other cultures, fasting is associated with at least an attitude of prayer, of seeking or petitioning God (or “the gods” in other cultures). What’s implied is a posture of humility before God.

in Daniel, you may not be surprised that Daniel fasted, we see that a couple times:

​Daniel 9:3 CSB
3 So I turned my attention to the Lord God to seek him by prayer and petitions, with fasting, sackcloth, and ashes.

Daniel 10:1–3 CSB
1 In the third year of King Cyrus of Persia, a message was revealed to Daniel, who was named Belteshazzar. The message was true and was about a great conflict. He understood the message and had understanding of the vision. 2 In those days I, Daniel, was mourning for three full weeks. 3 I didn’t eat any rich food, no meat or wine entered my mouth, and I didn’t put any oil on my body until the three weeks were over.

What you might not expect is that not only Daniel, but king Darius fasted, after Daniel was thrown into the lions’ den by Darius’s own decree:

Daniel 6:18 CSB
18 Then the king went to his palace and spent the night fasting. No diversions were brought to him, and he could not sleep.

Again, a reminder that fasting was a familiar practice not just for Israel, but for surrounding cultures as well. 

There are quite a few other examples of fasting throughout the Old Testament, this certainly wasn’t all of them, but I do think this selection is representative of the context and general purpose of fasting in ancient Jewish culture.

Fasting in the New Testament

And of course we have to remember that this is the culture in which Jesus was raised, and in which Jesus was preaching.

The precursor to Jesus, the first main character in the story of the gospel, is described as regularly fasting. John the Immerser. To me, it makes sense that he would fast, because he was preparing the way for the Messiah, anticipating the arrival of, in one sense, “the day of the Lord,” not the final one, but that would certainly be what he was preparing for. In fact, not only John but also his disciples are described as regularly fasting along with the pharisees, and they ask why Jesus and his disciples don’t do the same!

We see this in Matthew chapter 9:

Matthew 9:14 CSB
14 Then John’s disciples came to him, saying, “Why do we and the Pharisees fast often, but your disciples do not fast?”

It’s funny, Jesus and his disciples are described in a couple places in contrast to John, even though Jesus began his ministry with a 40 day fast in the wilderness, right after his baptism by John (we read about that back in Matthew 4) and clearly in Jesus’s sermon, he is expecting his followers to fast, he’s just saying not to make it obvious. 

In the next verse, we’ll see Jesus defend his disciple’s lack of fasting at that time, by making a comparison to a wedding, basically saying that because Jesus was there with them in that moment, it was a time for celebration and feasting, not mourning and fasting:

​Matthew 9:15 CSB
15 Jesus said to them, “Can the wedding guests be sad while the groom is with them? The time will come when the groom will be taken away from them, and then they will fast.

We also see fasting associated with worship in the New Testament, in Luke and Acts:

Luke 2:36–37 CSB
36 There was also a prophetess, Anna, a daughter of Phanuel, of the tribe of Asher. She was well along in years, having lived with her husband seven years after her marriage, 37 and was a widow for eighty-four years. She did not leave the temple, serving God night and day with fasting and prayers.

Fasting is described in this context as a way of actually serving God, or worshipping God. We see similar phrasing in Acts:

Acts 14:23 CSB
23 When they had appointed elders for them in every church and prayed with fasting, they committed them to the Lord in whom they had believed.

Should We Fast? When? How?

Fasting has a rich history in the Old Testament, and the tradition was continued by Jesus and his followers into the New Testament, so the question remains: what about us? Should we fast? If so, how do we fast? When do we fast?

The other two practices he brought up, giving to the poor and praying, those two things ARE explicitly commanded all throughout scripture, in all kinds of contexts! Fasting, not so much!

There are no specific commands to fast, even in the Old Testament the only command in which fasting is implied is related to the day of atonement, which Jesus fulfilled once and for all. It’s certainly not one of the ten commandments, and in the New Testament, while Jesus did fast he was much more known for feasting and partying! He was accused of being a glutton and a drunkard! Of course, he wasn’t, but that was the caricature painted of him, in stark contrast to the austere image of John the immerser.

(Note: compared to fasting, there ARE plenty of examples of feasts which are actually prescribed throughout the law).

And yet, even after the death, burial, and resurrection of Jesus, his followers still saw fit to fast for various reasons.

I think it’s important to realize that when Jesus is talking about fasting here in Matthew 6, he’s expecting his disciples to fast, but he’s not commanding them to. He’s not commanding them NOT to, either! He knows it’s ingrained in their culture, it’s part of how they mourn, how they pray, and he’s giving them some guidance on how to do it properly. He’s condoning the practice, so long as it’s practiced humbly and privately, but he’s not necessarily commanding it.

Compared to the previous two examples, fasting seems to have more significance culturally than it does theologically, but regardless, the point Jesus is making, the warning about motives applies equally. 

There was an assumption that his disciples would be fasting, so Jesus wanted to caution them to be fasting with the right intentions. Fasting isn’t necessarily such a given, it’s not quite so ingrained in our culture, is it? There’s not a huge emphasis on it, in my experience, in modern American protestant traditions, is it? Certainly not compared to how regularly the Jews did it, or even compared to how many other cultures around the world still practice it today. 

Colombian/South American Culture

I got to talk with Conner and Valeria a little bit about their experience in Colombia, which in this case I think is fairly representative of South American culture in general, where it’s much more common for churches to practice fasting, both corporately and privately, almost as regularly as we practice prayer, or sing worship songs, or celebrate communion, fasting is part of their regular rhythms, every week or more! It might mean fasting just for half a day, or a full day or 24 hours, or sometimes for longer periods, and they told me their church there even had rooms where people could stay and fast and pray for days at a time if they needed to. Just to give you an idea of how much more common and integrated this spiritual discipline is in their church life in that part of the world, and from what they told me this is true across most, if not all Christian denominations in Colombia.

I think there is something that can be learned from other cultures, that may be somewhat lacking in our current church culture.

Benefits of Fasting (Or Denying Ourselves)

While there is no specific ordinance where Christians are commanded to fast, and yes, you can be a Christian, and even a spiritually mature Christian, without fasting, that doesn’t mean we should never fast!

Of course, there are some people who for medical reasons should NOT fast, at least not in the sense of abstaining from food. There may be other ways to “fast” which I’ll get to in a moment. But some people should not abstain from food, and that’s totally fine, but the vast majority of people can safely choose to not eat for 6, 12, or 24 hours. In fact, there have been a lot of studies suggesting there can be significant health benefits to fasting! So, even physically it can be beneficial.

But, more importantly there are spiritual benefits to fasting:

  • Emphasizes spiritual priorities over physical desires.
    • Frees up time/space in our life to dedicate to prayer and meditation.
  • Often we base a lot of our decisions and structure our day around our meals!
  • Reminds us that we rely on God, not ourselves, to survive.

So yes, I do think it’s a good idea for most of us to incorporate fasting into our lives, even if it’s not every week, or even every month, we should recognize it as a beneficial practice which helps us hone our focus on God and dedicate ourselves to prayer and meditation.

If for no other reason, I think it makes sense to fast, because Jesus fasted! Yes, that was partly because of the culture he grew up in, but it was clearly important to him as part of his spiritual life and preparation for his ministry.

When to Fast

Taking cues from OT stories and Jesus’s Example, appropriate times to fast are:

Out of grief - this isn’t usually part of our culture, but it could potentially be a healthy part of going through the mourning process, actually setting aside time to intentionally mourn and seek God’s presence.

Out of repentance - there is nothing magical about fasting which will bring about forgiveness - Jesus’s atonement covers our sins - but fasting can help us to refocus our spirit when we have wrong God and others, as well as demonstrate to God our commitment to following through with our new direction, away from what displeases him, by replacing it with something that does please him…spending time with him.

In preparation for a difficult decision or challenge in life - this is exactly when Jesus fasted, and one of the most significant reasons for fasting in the Old Testament. It’s always a good idea to spend time seeking God’s guidance during momentous seasons of life, and fasting can be an aid to making that happen.

Alternative/Analogous Forms of Fasting

If you can’t abstain from food, you can still gain many of the same benefits by abstaining form other things which usually occupy a significant portion of your life, for example:

  • Netflix
  • Social Media
  • Video Games
  • Sports
  • Etc

The idea being that you can choose to abstain from certain things which aren’t necessarily sinful (as long as they aren’t idols), but intentionally abstain from them for a set period of time, with the purpose of drawing closer to God, worshipping God, and seeking his guidance.


Fasting is a beneficial spiritual discipline with rich cultural history, which Jesus himself practiced. We would do well to consider incorporating it into our lives, but taking care not to make it a gimmick or spectacle, rather using it as a way to mark time dedicated to spiritual growth and turning our focus to God.

Sermon on the Mount: Fasting

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NCF was started in 1987 to minister to the growing population of Fort Drum and Jefferson County. Located in Carthage, just minutes away from Ft Drum, Lowville and Watertown, it is a blended congregation of local and military folks, single soldiers, young families and grandparents.