Alms, Prayer, & Fasting 6:1-18
Fasting vv. 16-18
There is only one fast declared in the Old Testament. On the Day of Atonement the Israelites were to fast (Le. 16:29, 31; 23:27-32; Nu. 29:7), meaning abstinence from food and drink for the twenty-four hour period from sunset to sunset. Later in Jewish history other fasts were added, mainly marking significant passages or disasters. This is why fasting expresses either/or grief and penitence.
Sometimes fasting was personal — a time of “afflicting the soul”, and often it indicated pious self-discipline (Pharisees fasted every Monday and Thursday). Fasting’s achilles heel, however, was public display.
This is what Jesus warns his disciples against. Just as was the case with almsgiving and prayer, Jesus saw both the value and the danger. Self-satisfaction, showing off, and phone contrition very easily trumped the essential spiritual quality of genuine fasting. Too easily we humans can yield to the “pride that apes humility”.
So, says Jesus, turn human display and look solely to heaven. Let God see your good work. Don’t give anyone else even a hint of what you’re up to. The Lord will “give back” (“reward”) to those who give to him. But don’t think for a minute that fasting guarantees a heavenly hearing. The Old Testament prophets made it very clear (See Is. 58:5-12) that fasting provided no smoke screen for unjust/unrighteous behavior.