What is the purpose of fasting?

Biblically, the primary purpose for fasting is to humble the body before God during prayers for petition and confession of sin. Secondly, it is part of the process of mourning. Yom Kippur, or the Day of Atonement, was sanctified as a day of rest and fasting once a year for the purpose of cleansing the Israelites from their sins (Leviticus 16:29-34, 23:26-32, Numbers 29:7-11). Typically, fasting was the abstinance of food and water for a certain period of time, while wearing sackcloth and ashes. As the psalmist says, "Yet when they were ill, I put on sackcloth and humbled myself with fasting. When my prayers returned to me unanswered, I went about mourning as though for my friend or brother. I bowed my head in grief as though weeping for my mother" (Psalm 35:13-14). Other scriptural passages that depict fasting as a humbling experience for the purpose of petition and confession include the following:

  • Exodus 34:28, "Moses was there with the LORD forty days and forty nights without eating bread or drinking water. And he wrote on the tablets the words of the covenant -- the Ten Commandments."

  • Deuteronomy 9:9-19, "When I went up on the mountain to receive the tablets of stone, the tablets of the covenant that the LORD had made with you, I stayed on the mountain forty days and forty nights; I ate no bread and drank no water. The LORD gave me two stone tablets inscribed by the finger of God. On them were all the commandments the LORD proclaimed to you on the mountain out of the fire, on the day of the assembly. At the end of the forty days and forty nights, the LORD gave me the two stone tablets, the tablets of the covenant. Then the LORD told me, 'Go down from here at once, because your people whom you brought out of Egypt have become corrupt. They have turned away quickly from what I commanded them and have made a cast idol for themselves.' And the LORD said to me, 'I have seen this people, and they are a stiffed-neck people indeed! Let me alone, so that I may destroy them and blot out their name from under heaven. And I will make you into a nation stronger and more numerous than they.' So I turned and went down from the mountain while it was ablaze with fire. And the two stone tablets of the covenant were in my hands. When I looked, I saw that you had sinned against the LORD your God; you had made for yourselves an idol cast in the shape of a calf. You had turned aside quickly from the way that the LORD had commanded you. So I took the two tablets and threw them out of my hands, breaking them to pieces before your eyes. Then once again I fell prostrate before the LORD for forty days and forty nights; I ate no bread and drank no water, because of all the sin you had committed, doing what was evil in the LORD's sight and so provoking him to anger. I feared the anger and the wrath of the LORD, for he was angry enough with you to destroy you. But again the LORD listened to me."

  • 1 Samuel 7:5-6, "Then Samuel said, 'Assemble all Israel at Mizpah and I will intercede with the LORD for you.' When they had assembled at Mizpah, they drew water and poured it out before the LORD. On that day they fasted and there they confessed, 'We have sinned against the LORD.' And Samuel was leader of Israel at Mizpah."

  • 1 Kings 21:27-28, "When Ahab heard these words, he tore his clothes, put on sackcloth and fasted. He lay in sackcloth and went around meekly. Then the word of the LORD came to Elijah the Tishbite: 'Have you noticed how Ahab has humbled himself before me? Because he has humbled himself, I will not bring this disaster in his day, but I will bring it on his house in the days of his son.' "

  • 2 Chronicles 20:2-4, "Some men came and told Jehoshaphat, 'A vast army is coming against you from Edom, from the other side of the Sea. It is already in Hazazon Tamar' (that is, En Gedi). Alarmed, Jehoshaphat resolved to inquire of the LORD, and he proclaimed a fast for all Judah. The people of Judah came together to seek help from the LORD; indeed, they came from every town in Judah to seek him."

  • Ezra 8:21-23, "There, by the Ahava Canal, I proclaimed a fast, so that we might humble ourselves before our God and ask him for a safe journey for us and our children, with all our possessions. I was ashamed to ask the king for soldiers and horsemen to protect us from enemies on the road, because we had told the king, 'The gracious hand of our God is on everyone who looks to him, but his great anger is against all who forsake him.' So we fasted and petitioned our God about this, and he answered our prayer."

  • Nehemiah 9:1-3, "On the twenty-fourth day of the same month, the Israelites gathered together, fasting and wearing sackcloth and having dust on their heads. Those of Israelite descent had separated themselves from all foreigners. They stood in their places and confessed their sins and the wickedness of their fathers. They stood where they were and read from the Book of the Law of the LORD their God for a quarter of the day, and spent another quarter in confession and in worshiping the LORD their God."

  • Esther 4:15-16, "Then Esther sent this reply to Mordecai: 'Go, gather all the Jews who are in Susa, and fast for me. Do not eat or drink for three days, night or day. I and my maids will fast as you do. When this is done, I will go to the king, even though it is against the law. And if I perish, I perish.' "

  • Jonah 3:5-10, "The Ninevites believed God. They declared a fast, and all of them, from the greatest to the least, put on sackcloth. When the news reached the king of Nineveh, he rose from his throne, took off his royal robes, covered himself with sackcloth and sat down in the dust. Then he issued a proclamation in Nineveh: 'By the decree of the king and his nobles: Do not let any man or beast, herd or flock, taste anything; do not let them eat or drink. But let man and beast be covered with sackcloth. Let everyone call urgently on God. Let them give up their evil ways and their violence. Who knows? God may yet relent and with compassion turn from his fierce anger so that we will not perish.' When God saw what they did and how they turned from their evil ways, he had compassion and did not bring upon them the destruction he had threatened."

  • Jeremiah 36:1-10, "...So Jeremiah called Baruch son of Neriah, and while Jeremiah dictated all the words the LORD had spoken to him, Baruch wrote them on the scroll. Then Jeremiah told Baruch, 'I am restricted; I cannot go to the LORD's temple. So you go to the house of the LORD on a day of fasting and read to the people from the scroll the words of the LORD that you wrote as I dictated. Read them to all the people of Judah who come in from their towns. Perhaps they will bring their petition before the LORD, and each will turn from his wicked ways, for the anger and wrath pronounced against this people by the LORD are great...' "

  • Daniel 9:1-3, "In the first year of Darius son of Xerxes (a Mede by descent), who was made ruler over the Babylonian kingdom -- in the first year of his reign, I, Daniel, understood from the Scriptures, according to the word of the LORD given to Jeremiah the prophet, that the desolation of Jerusalem would last seventy years. So I turned to the LORD God and pleaded with him in prayer and petition, in fasting, and in sackcloth and ashes."

        Then the LORD said to me, "Do not pray for the well-being of this people. Although they fast, I will not listen to their cry; though they offer burnt offerings and grain offerings, I will not accept them. Instead, I will destroy them with sword, famine and plague." (Jeremiah 14:11-12)

It would seem as though the Israelites, or at least the priests and teachers of the law, had customarily set aside one or two days out of the week to fast, however, it became more of a tradition of show than a heart-felt experience. As Jesus pointed out in Luke 18:9-14, the Pharisee who exalted himself in prayer about fasting twice a week and tithing ten percent was not justified before God and would have done more to humble himself by admitting that he was a sinner in need of mercy. Isaiah 58:3-9 also points out the attitude of the Israelites who set aside one day of the year for fasting as a show of humbleness, but God was not satisfied with this and replied, "Yet on the day of fasting, you do as you please and exploit all your workers. Your fasting ends in quarreling and strife, and in striking each other with wicked fists. You cannot fast as you do today and expect your voice to be heard on high. Is this the kind of fast I have chosen, only a day for a man to humble himself? Is it only for bowing one's head like a reed and for lying on sackcloth and ashes? Is that what you call a fast, a day acceptable to the LORD? Is not this the kind of fasting I have chosen: to loose the chains of injustice and untie the cords of the yoke, to set the oppressed free and break every yoke? Is it not to share your food with the hungry and to provide the poor wanderer with shelter -- when you see the naked, to clothe him, and not to turn away from your own flesh and blood? Then your light will break forth like the dawn, and your healing will quickly appear; then your righteousness will go before you, and the glory of the LORD will be your rear guard. Then you will call, and the LORD will answer; you will cry for help, and he will say: Here am I." God is not debunking the act of fasting, rather, he is rebuking the erroneous attitudes of the heart that accompanied it. Rather than focusing on our own needs and the outward self-denial of necessity, we should rather spend ourselves "in behalf of the hungry and satisfy the needs of the oppressed" (Isaiah 58:10).

        "Who are you, Lord?" Saul asked. "I am Jesus, whom you are persecuting," he replied. "Now get up and go into the city, and you will be told what you must do." The men travelling with Saul stood there speechless; they heard the sound but did not see anyone. Saul got up from the ground, but when he opened his eyes he could see nothing. So they led him by the hand to Damascus. For three days he was blind, and he did not eat or drink anything... Then Ananias went to the house and entered it. Placing his hands on Saul, he said, "Brother Saul, the Lord -- Jesus, who appeared to you on the road as you were coming here -- has sent me so that you may see again and be filled with the Holy Spirit." Immediately, something like scales fell from Saul's eyes, and he could see again. He got up and was baptized, and after taking some food, he regained his strength. (Acts 9:5-9, 17-19)

Here are scriptural examples of those who fasted in mourning. Some are fasts for the purpose of mourning for the sins of the people of Israel, coupled with petitions to the LORD for compassion. From some of these occassions came annual celebrations which included fasting, such as Purim (Esther 9:26-32) and the return from Babylonian captivity (Zechariah 8:18-19).

  • Judges 20:26-28, "Then the Israelites, all the people, went up to Bethel, and there they sat weeping before the LORD. They fasted that day until evening and presented burnt offerings and fellowship offerings to the LORD. And the Israelites inquired of the LORD. (In those days the ark of the covenant of God was there, with Phinehas son of Eleazar, the son of Aaron, ministering before it.) They asked, 'Shall we go up again to battle with Benjamin our brother, or not?' The LORD responded, 'Go, for tomorrow I will give them into your hands.' "

  • 1 Samuel 31:11-13, "When the people of Jabesh Gilead heard of what the Plilistines had done to Saul, all their valiant men journeyed through the night to Beth Shan. They took down the bodies of Saul and his sons from the wall of Beth Shan and went to Jabesh, where they burned them. Then they took their bones and buried them under a tamarisk tree at Jabesh, and they fasted seven days." 2 Samuel 1:11-12, "Then David and all the men with him took hold of their clothes and tore them. They mourned and wept and fasted till evening for Saul and his son Jonathan, and for the army of the LORD and the house of Israel, because they had fallen by the sword." (Also 1 Chronicles 10:11-12.)

  • 2 Samuel 3:31-35, "Then David said to Joab and all the people with him, 'Tear your clothes and put on sackcloth and walk in mourning in front of Abner.' King David himself walked behind the bier. They buried Abner at Hebron, and the king wept aloud at Abner's tomb. All the people wept also... Then they all came and urged David to eat something while it was still day; but David took an oath, saying, 'May God deal with me, be it ever so severely, if I taste bread or anything else before the sun sets!' "

  • 2 Samuel 12:15-23, "After Nathan had gone home, the LORD struck the child that Uriah's wife had borne to David, and he became ill. David pleaded with God for the child. He fasted and went into his house and spent the nights lying on the ground. The elders of his household stood beside him to get him up from the ground, but he refused, and he would not eat any food with them. On the seventh day the child died... Then David got up from the ground. After he had washed, put on lotions and changed his clothes, he went into the house of the LORD and worshiped. Then he went to his own house, and at his request they served him food, and he ate. His servants asked him, 'Why are you acting this way? While the child was alive, you fasted and wept, but now that the child is dead, you get up and eat!' He answered, 'While the child was still alive, I fasted and wept. I thought, 'Who knows? The LORD may be gracious to me and let the child live.' But now that he is dead, why should I fast? Can I bring him back again? I will go to him, but he will not return to me.' "

  • Ezra 10:6, "Then Ezra withdrew from before the house of God and went to the room of Jehohanan son of Eliashib. While he was there, he ate no food and drank no water, because he continued to mourn over the unfaithfulness of the exiles."

  • Nehemiah 1:3-4, "They said to me, 'Those who survived the exile and are back in the province are in great trouble and disgrace. The wall of Jerusalem is broken down, and its gates have been burned with fire.' When I heard these things, I sat down and wept. For some days I mourned and fasted and prayed before the God of heaven."

  • Esther 4:3, "In every province to which the edict and order of the king came, there was great mourning among the Jews, with fasting, weeping and wailing. Many lay in sackcloth and ashes."

  • Joel 1:13-14, "Put on sackcloth, O priests, and mourn; wail, you who minister before the altar. Come, spend the night in sackcloth, you who minister before my God; for the grain offerings and drink offerings are withheld from the house of your God. Declare a holy fast; call a sacred assembly. Summon the elders and all who live in the land to the house of the LORD your God, and cry out to the LORD."

  • Joel 2:12-17, "Even now," declares the LORD, "return to me with all your heart, with fasting and weeping and mourning." Rend your hearts and not your garments. Return to the LORD your God, for he is gracious and compassionate, slow to anger and abounding in love, and he relents from sending calamity. Who knows, he may turn and have pity and leave behind a blessing -- grain offerings and drink offerings for the LORD your God. Blow the trumpet in Zion, declare a holy fast, call a sacred assembly. Gather the people, concecrate the assembly; bring together the elders, gather the children, those nursing at the breast. Let the bridegroom leave his room and the bride her chamber. Let the priests, who minister before the LORD, weep between the temple porch and the altar. Let them say, "Spare your people, O LORD. Do not make your inheritance an object of scorn, a byword among the nations. Why should they say among the peoples, 'Where is their God?' "

  • Zechariah 7:3-6, "Should I mourn and fast in the fifth month, as I have done for so many years?" Then the word of the LORD Almighty came to me: "Ask all the people of the land and the priests, 'When you fasted and mourned in the fifth and seventh months for the past seventy years, was it really for me that you fasted? And when you were eating and drinking, were you not just feasting for yourselves?' "

  • Matthew 9:14-15, "Then John's disciples came and asked him, 'How is it that we and the Pharisees fast, but your disciples do not fast?' Jesus answered, 'How can the guests of the bridegroom mourn while he is with them? The time will come when the bridegroom will be taken from them; then they will fast.' " (Also Mark 2:18-20 and Luke 5:33-35.)

        "When you fast, do not look somber as the hypocrites do, for they disfigure their faces to show men they are fasting. I tell you the truth, they have received their reward in full. But when you fast, put oil on your head and wash your face, so that it will not be obvious to men that you are fasting, but only to your Father, who is unseen; and your Father, who sees what is done in secret, will reward you." (Matthew 6:16-18)


Jesus fasted for forty days in the desert after being baptized, according to Matthew 4:1-2 and Luke 4:1-2, for the purpose of being tempted by the devil. When the devil told him to turn stones to bread, Jesus' reply was ,"It is written: 'Man does not live on bread alone, but on every word that comes from the mouth of God' [Deuteronomy 8:3]" (Mathew 4:4). Aside from this, not much insight is given in the New Testament in regards to fasting. Jesus did teach that, contrary to the Old Testament method of an outward show of fasting for the sake of scorn (Psalm 69:10-12, 109:24-25, Isaiah 58:5), that fasting was a private matter to be hidden from others (Matthew 6:16-18). In this, he also points out that there is reward for fasting. Some scriptural interpretations include fasting with prayer as a means of casting out difficult demons (Matthew 17:21 and Mark 9:29). In Acts 13:1-3 and 14:23, Paul and those with him use fasting with prayer and worship in the process of appointing elders and setting apart those chosen to go and do God's work. In his letter to the Romans, Paul writes that in whatever we do, whether considering one day more sacred than another or abstaining from food, that we should be fully convinced in our own mind that what we do, we do for the Lord and give thanks to God (Romans 14:5-8). In regards to the duration of a fast, most of those cited above fasted for as long as was required for God to acknowledge them. It should also be pointed out that not all fasting is complete abstinance from both solid food and liquid. According to Daniel 10:3, Daniel fasted for three weeks by abstaining from choice food, such as meat and wine, which was considered humbling before God (Daniel 10:12), and his prayers were answered as soon as he had set his mind to it.

        "At that time I, Daniel, mourned for three weeks. I ate no choice food; no meat or wine touched my lips; and I used no lotions at all until the three weeks were over. On the twenty-fourth day of the first month, as I was standing on the bank of the great river, the Tigris, I looked up and there before me was a man dressed in linen, with a belt of the finest gold around his waist. His body was like chrysolite, his face like lightning, his eyes like flaming torches, his arms and legs like the gleam of burnished bronze, and his voice like the sound of a multitude... 'Do not be afraid, Daniel. Since the first day that you set your mind to gain understanding and to humble yourself before your God, your words were heard, and I have come in response to them. But the prince of the Persian kingdom resisted me twenty-one days. Then Michael, one of the chief princes, came to help me, because I was detained there with the king of Persia. Now I have come to explain to you what will happen to your people in the future, for the vision concerns a time yet to come.' " (Daniel 10:2-14)

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