1 “(But) take care not to perform righteous deeds in order that people may see them; otherwise, you will have no recompense from your heavenly Father. 2 When you give alms, do not blow a trumpet before you, as the hypocrites do in the synagogues and in the streets to win the praise of others. Amen, I say to you, they have received their reward. 3 But when you give alms, do not let your left hand know what your right is doing, 4 so that your almsgiving may be secret. And your Father who sees in secret will repay you. 5 “When you pray, do not be like the hypocrites, who love to stand and pray in the synagogues and on street corners so that others may see them. Amen, I say to you, they have received their reward. 6 But when you pray, go to your inner room, close the door, and pray to your Father in secret. And your Father who sees in secret will repay you…. 16 “When you fast, do not look gloomy like the hypocrites. They neglect their appearance, so that they may appear to others to be fasting. Amen, I say to you, they have received their reward. 17 But when you fast, anoint your head and wash your face, 18 so that you may not appear to be fasting, except to your Father who is hidden. And your Father who sees what is hidden will repay you.
Three religious practices that would have been especially important for the Pharisees are treated in the third major part of the Sermon on the Mount (6:1–18). After stating the general principle that religious acts should be done to honor God and not simply to better one’s own reputation (v. 1), the passage considers almsgiving (vv. 2–4), prayer (vv. 5–15), and fasting (vv. 16–18). Each section contains a description of behavior that should be avoided, an instruction on the proper attitude, and the promise of a reward from God. Pious self-display is criticized, not the pious actions in themselves.
In a society without a highly organized welfare system, the obligation to offer charity (vv. 2–4) to the poor, the defenseless, and the sick was taken very seriously by religious people. In verse 2 Jesus criticizes those who make a great display of their charity by means of the image of blowing a horn. He calls such people “hypocrites,” a term that originally referred to actors on a stage but here carries the sense of “phonies.” The charge of hypocrisy is also leveled against the scribes and Pharisees in chapter 23. Jesus’ disciples are instructed to be so free from religious showiness that they do not even seek the self-satisfaction of knowing what they are giving (6:3). Both verses 2 and 3 rely on obvious exaggerations in order to contrast self-seeking and selflessness in religion. The God who sees acts hidden from human sight will surely reward charity given without fanfare (v. 4).
The section on prayer begins the same way as the preceding section did. Here the behavior to be avoided is making a public spectacle of oneself in prayer (v. 5). The only fitting reward for such prayer is the public notoriety that it attracts. Indeed, prayer offered to win human praise is not prayer at all. Jesus’ disciples are instructed to avoid making a public display of themselves in prayer (v. 6). That public prayer should be condemned outright was unthinkable for Jews like Jesus and Matthew, and it is not condemned here. Rather, another exaggerated statement is used in order to underline the warning against religious showiness. God will reward only genuine prayer offered in sincerity to him.
The section on fasting follows the pattern set in the sections on almsgiving and prayer. There were special days designated for fasting in the Jewish calendar, and pious Pharisees fasted two days a week. Not the act of fasting itself, but rather making a public display of one’s fast, is criticized in verse 16. Jesus’ disciples are instructed to disguise their fasting by looking as if they are preparing for a holiday (v. 17). God will know that they are fasting and will reward them accordingly (v. 18).
Daniel J. Harrington, S.J., Matthew in The Collegeville Bible Commentary (Collegeville, MN: Liturgical Press, 1989) 871-872