And whenever you fast, do not put on a gloomy face as the hypocrites do, for they neglect their appearance in order to be seen fasting by men. Truly I say to you, they have their reward in full. (Matthew 6:16)
During Old Testament times many faithful believers fasted-Moses, Samson, Samuel, Hannah, David, Elijah, Ezra, Nehemiah, Esther, Daniel, and many others. And the New Testament tells us of the fasting of Anna, John the Baptist and his disciples, Jesus, Paul, and numerous others. We know that many of the early church Fathers fasted, and that Luther, Calvin, Wesley, Whitefield, and many other outstanding Christian leaders have fasted.
But the only fast commanded in Scripture is the one connected with the Day of Atonement. On that day all the people were to “humble [their] souls” (Lev. 16:29; cf. 23:27), a Hebrew expression that included forsaking food as an act of self-denial. That was a national fast, involving every man, woman, and child in Israel. But it occurred only one time a year, and then only as an integral part of the Day of Atonement.
Because it is not elsewhere commanded by God, fasting is unlike giving and praying, for which there are many commands in both testaments. Both the Old and New Testaments speak favorably of fasting and record many instances of fasting by believers. But except for the yearly fast just mentioned, it is nowhere required. Beyond that, fasting is shown to be an entirely noncompulsory, voluntary act, not a spiritual duty to be regularly observed.
The phrase and whenever you fast supports the understanding that fasting is not commanded. But when it is practiced it is to be regulated according to the principles Jesus gives here.
Nesteia (fast) literally means not to eat, to abstain from food. Fasts were sometimes total and sometimes partial, and ordinarily only water was drunk.
Two extreme views of eating were held among the Jews of Jesus’ day. Many, like the ones mentioned in this passage, made an obvious display of fasting. Others believed that, because food is a gift from God, each person would have to give an account to Him on the day of judgment for every good thing he had not eaten. The first group not only was more prevalent but was more self-righteous and proud. Their fasting was not a matter of spiritual conviction but a means of self-gratification.
By the time of Christ, fasting, like almost every other aspect of Jewish religious life, had been perverted and twisted beyond what was scriptural and sincere. Fasting had become a ritual to gain merit with God and attention before men. Like praying and almsgiving, it was largely a hypocritical religious show.