The disciples of John the Baptist and those of the Pharisees often practiced fasting in connection with prayer (Lk. 5:33). First-century Pharisees lived a very rigid life of self-discipline; however, the disciples of Jesus ate and drank as they followed Him without following a strict schedule of prayers and fasting. Jesus was asked about this difference and gave three illustrations to answer why His disciples did not fast at that time. First, Jesus described Himself as the groom and the disciples as his friends (v. 34). As friends of the bridegroom, they were to enjoy being with Him. While the bridegroom was there with them, they needed to be learning from Him and enjoying His presence, rather than being isolated, weeping and mourning over sins. Soon enough the time would come when Jesus would be arrested, crucified, and raised to go into heaven. Then, when He was away from them, they would fast (v. 35). Second, Jesus refers to a piece of new cloth put into old clothing (v. 36). An unshrunk cloth sewn into an old garment would pull and make the tear worse (cf. Mt. 9:16; Mk. 2:21). The two did not match. Third, Jesus said new wine—unfermented grape juice—needed new wineskins (Lk. 5:37-39). Though the KJV has the term “bottles,” Jesus is not referring to modern glass bottles. Dehaired skins of small animals, such as goats, were sewn together in those days to hold beverages such as water (Gen 21:15), milk (Judges 4:19), and wine (Josh 9:4, 13). Old wineskins were already stretched from the aging process of the wine and had lost their elasticity. The new was not compatible with the old. Jesus was not going to push a strict fasting routine on the disciples for which they were not ready. They were still spiritual babes and needed time to grow. The Bible does not regulate the frequency of fasting, but builds upon the practice by highlighting proper motivations. Jesus taught that fasting should occur during especially appropriate situations.
According to the Scriptures there are different reasons for fasting. Some fasting is done out of necessity—not eating because there is no food. The reason Jesus multiplied food to feed the four thousand was because they had been following Him for three days and had no food; He did not want to send the multitude away fasting and for them to become faint on the return trip (Mt. 15:32). Jesus travelled often, which is not conducive to fasting. Sometimes fasting is a natural reaction to trauma. David had a child that was very sick to the point of death, and though he was encouraged to eat, he did not (2 Sam. 12:16-17). This was a time of tremendous grief for David. He was not inclined to eat. When Saul died, the valiant men buried him in Jabesh and fasted seven days (1 Chron. 10:12). Often when the death of a loved one occurs, you just don’t feel hungry. That kind of distress naturally causes you to not want to eat. Sometimes people fast when they are expressing sorrow for sin (Jonah 3:5). If we are upset over our transgressions and focusing on the guilt of our sins, then it isn’t the time to eat (Ecc. 3:4).
Fasting, in the sense of choosing to go without food for a period of time, may accompany major trials, challenges, and important works. Moses fasted when receiving the law (Ex. 34:28). Daniel fasted and prayed during his concern over the desolation of his homeland (Dan. 9-10). Jesus told his disciples that some demons would only be cast out through prayer and fasting (Mt. 17:21). Fasting and prayer accompanied sending out Paul and Barnabas to missionary work (Acts 13:2-3), and when they, in turn, ordained elders in the congregations they had planted (Acts 14:23). As an exception to regular intimacy in marriage, Paul said that husbands and wives can consent to abstain for a time to give themselves to fasting and prayer (1 Cor. 7:5). Thus, fasting is appropriate for Christians at times of special, spiritual meditation to get away from distractions and focus on the Lord.