16 "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. 17 But when you fast, put oil on your head and wash your face, 18 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.
Fasting must be done in secret (as much as possible. Obviously, family members might know). If it is done in secret, God promises to reward you. And the rewards of fasting are great.
Jesus fasted for 40 days before beginning his miraculous ministry.
1 Then Jesus was led by the Spirit into the desert to be tempted by the devil. 2 After fasting forty days and forty nights, he was hungry. 3 The tempter came to him and said, "If you are the Son of God, tell these stones to become bread." 4 Jesus answered, "It is written: 'Man does not live on bread alone, but on every word that comes from the mouth of God.'"
If Jesus needed to fast, how much more we need to fast for wisdom, strength, power, deliverance, etc.
Fasting for wisdom.
26 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. 27 And the Israelites inquired of the LORD. (In those days the ark of the covenant of God was there, 28 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."
23 Paul and Barnabas appointed elders for them in each church and, with prayer and fasting, committed them to the Lord, in whom they had put their trust.
Fasting with confession of sin.
1 On the twenty-fourth day of the same month, the Israelites gathered together, fasting and wearing sackcloth and having dust on their heads. 2 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. 3 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.
3 So I turned to the Lord God and pleaded with him in prayer and petition, in fasting, and in sackcloth and ashes. 4 I prayed to the LORD my God and confessed: "O Lord, the great and awesome God, who keeps his covenant of love with all who love him and obey his commands, 5 we have sinned and done wrong. We have been wicked and have rebelled; we have turned away from your commands and laws.
4 On the first day, Jonah started into the city. He proclaimed: "Forty more days and Nineveh will be overturned." 5 The Ninevites believed God. They declared a fast, and all of them, from the greatest to the least, put on sackcloth. 6 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. 7 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. 8 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. 9 Who knows? God may yet relent and with compassion turn from his fierce anger so that we will not perish." 10 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.
4 When I heard these things, I sat down and wept. For some days I mourned and fasted and prayed before the God of heaven. 5 Then I said: "O LORD, God of heaven, the great and awesome God, who keeps his covenant of love with those who love him and obey his commands, 6 let your ear be attentive and your eyes open to hear the prayer your servant is praying before you day and night for your servants, the people of Israel. I confess the sins we Israelites, including myself and my father's house, have committed against you. 7 We have acted very wickedly toward you. We have not obeyed the commands, decrees and laws you gave your servant Moses.
Fasting for deliverance.
2 Chronicles 20:2-4
2 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). 3 Alarmed, Jehoshaphat resolved to inquire of the LORD, and he proclaimed a fast for all Judah. 4 The people of Judah came together to seek help from the LORD; indeed, they came from every town in Judah to seek him.
These are just a few of the numerous people in the Bible who fasted and were blessed by God.
Fasting can be done in different ways.
A total fast = no food at all. This is how Jesus fasted. Moses also fasted this way twice for 40 days each.
A partial fast = generally no meat, bread or sweets; just vegetables, eggs, oatmeal, etc. Daniel fasted in this way.
12 "Please test your servants for ten days: Give us nothing but vegetables to eat and water to drink. 13 Then compare our appearance with that of the young men who eat the royal food, and treat your servants in accordance with what you see." 14 So he agreed to this and tested them for ten days. 15 At the end of the ten days they looked healthier and better nourished than any of the young men who ate the royal food. 16 So the guard took away their choice food and the wine they were to drink and gave them vegetables instead.
2 At that time I, Daniel, mourned for three weeks. 3 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.
Just like giving and praying, God's people are expected to fast.
Jesus said, "When you fast," not "if you fast."
17 But when you fast, put oil on your head and wash your face, 18 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.