Matt. 9:15; Mark 2:20; Luke 5:35 - many non-Catholics frown upon the Church's pious practice of fasting, and say that fasting went away after the resurrection of Christ. But Jesus Himself says that His followers will fast once He is gone and does not object.
Matt. 6:16-18 - in fact, Jesus even gives instructions on how to fast. Jesus says, "Do not look dismal like the hypocrites, but look clean and refreshed."
Matt. 17-21; Mark 9:29 - Jesus teaches that only prayer and fasting had special power to cure a man possessed by a demon. Jesus teaches about the efficacy of fasting and how fasting, coupled with prayer, is acceptable and pleasing to God.
Luke 2:37 - Anna the widow worshiped God with fasting and prayer night and day. The Church has always taught that, by virtue of our priesthood conferred in baptism, our fasting participates in the priesthood of Christ by atoning for the temporal punishments due to our and other people’s sins.
Acts 13:2-3; 14:23 - the apostles engaged in prayer and fasting in connection with ordaining leaders of the Church. Prayer and fasting have always been the practice of the Church.
1 Tim. 4:3 - when Paul refers to doctrines that require abstinence from foods, some Protestants refer to this verse to condemn the Catholic Church's practice of fasting. But Paul is referring to abstinence and any other practice that is performed apart from Christ's teachings. Fasting, on the other hand, is done in obedience to Christ's teachings of taking up our cross and following Him, by participating in His sufferings so we can share in His glory. When citing this verse, these Protestants do not explain why Jesus prophesied that his followers would fast and why Jesus gave instructions on how to fast.
Ez. 8:21-23 - Ezra proclaims a fast as a prayer for humility and self-mortification and God responds. Our fasting is performed to remind us of our absolute reliance upon God.
Neh. 1:4; 9:1 - these texts also show the historical practice of fasting. Fasting atones for temporal punishment due to sin and repairs our relationship with God.
Tobit 12:8 - prayer is good when accompanied by fasting. Throughout salvation history, God has encouraged fasting to be coupled with prayer.
Judith 4:9-13 - the people of Israel humbled themselves with fasting and the Lord Almighty responds.
Esther 4:3,16 - people fasted for days to atone for sin. Although Jesus remits the eternal penalty of our sin, we can atone for temporal penalties due to our sin.
Psalm 35:13 - David says, "I afflicted myself with fasting." David recognized that fasting drew him closer to God. Fasting makes us aware of our dependency on God.
Psalm 69:10 - the Psalmist writes, "I humbled my soul with fasting." Fasting helps us become humble, and in our humility we unit ourselves with our humble God.
Jer. 36:9 - the peoples of Jerusalem and Judah declared a fast before the Lord.
Baruch 1:5 - they wept, fasted, and prayed before the Lord.
Dan. 9:3; 10:2-3 - Daniel sought God through fasting, and abstained from choice foods and wine for three weeks.
Joel 1:14; 2:12,15 - fasts are called to sanctify and turn oneself toward the Lord.
Jonah 3:5,10 - people of Nineveh proclaim a fast to appease God and God responds favorably.
1 Macc. 3:47; 2 Macc. 13:12 - Judas and his army fasted in prayer.