The Torah requires all Jews to fast on the Yom Kippur (Day of Atonement). A person undertaking the fast abstains from all food, drink, and sexual relations. The person fasting does not bathe, wash, or comb his hair. Jewish law prohibits showering, bathing, and washing on Yom Kippur. “It is forbidden to wash part of the body as it is forbidden to wash the whole body … it is forbidden to anoint part of the body with oil as it is forbidden to anoint the whole body” (b.Yoma 77b). In the days of the Master, people used olive oil hygienically the way we use soap and shampoo.
Yeshua’s teaching seems to contradict these traditional Yom Kippur prohibitions. Yeshua taught His disciples to anoint themselves with oil and wash their faces when fasting:
Whenever you fast, do not put on a gloomy face as the hypocrites do, for they neglect their appearance so that they will be noticed by men when they are fasting. Truly I say to you, they have their reward in full. But you, when you fast, anoint your head and wash your face so that your fasting will not be noticed by men, but by your Father who is in secret; and your Father who sees what is done in secret will reward you. (Matthew 6:16-18)
When our Master instructed His disciples to anoint themselves with oil and wash their faces while fasting, He was not referring to a community fast or national fast day such as the Yom Kippur (Day of Atonement). Yom Kippur is a public fast upon which everyone in the Jewish community is supposed to be fasting. The hypocrite with a gloomy face and unkempt hair would receive no sympathy or applause for his piety from others who were also required to fast the same day.
Yeshua’s instructions referred to undertaking private fasts. In Judaism, a person might undertake a period of personal fasting and abstinence for purposes of repentance or heightened supplication and prayer. Rabbi Yeshua warned his disciples to keep their private fasts private “so that you may not be seen fasting by men, but by your Father who is in secret; and your Father who sees in secret will repay you” (Matthew 6:18).
A public fast like the Day of Atonement presented no danger of fasting only for the sake of being seen by men since everyone was fasting. Therefore, we should not misconstrue Yeshua’s words as a criticism of the traditional Jewish prohibitions of Yom Kippur or public fasts. Instead, the Master criticized those who ostentatiously flaunted their discomfort while undertaking personal, private fasts.
Rabbi Yeshua expected His disciples to take on personal fasts. He did not say, “If you fast;” He said, “When you fast.” Fasting constitutes a regular part of Jewish piety. An entire tractate of the Talmud (Ta’anit) addresses the practice of fasting. But when we undertake a private fast for a personal reason, we should keep it private. Yeshua’s admonition could be paraphrased to say, “When you undertake a private fast, don’t make it obvious to everyone that you are fasting.”