In times of great personal distress or when a serious situation faced the community, many customarily prayed and fasted, eating no food from the time of getting up in the morning until their retiring for the night. According to ancient Jewish sources, the person fasting on the day of atonement was not to wash or anoint his body or any part thereof. If, however, any body part had become dirty with excrement or filth, he could wash, and the sick could anoint themselves with oil or put oil on a scab.

One way those engaging in frequent fasting made a display thereof was to blacken their faces with ashes. Concerning a prominent rabbi of ancient times (Joshua Ben Ananiah), it was said that his face was black from fasting. Those who fasted appear to have made themselves look as miserable as possible.

Jesus identified as hypocrites persons who fasted for others to notice them, because their main objective involved the manner in which observers would regard them instead of a sincere desire to reflect the intensity of their appeal to God. Therefore, as Jesus had said about wrongly motivated prayer, such persons had received their reward. Whatever expressions of praise observers would make constituted the one and only recompense. (Matthew 6:16)

The Son of God taught his disciples to avoid making a show respecting personal fasting, not altering their appearance in any way. Instead, they were to wash their faces and put oil (commonly olive oil) on their heads. The oil would protect the exposed areas of the head and neck from the penetrating rays of the sun and would keep the skin supple. Jesus’ Father would take note of the sincere fasting, though done in secret or hidden from human view, and would respond favorably to the appeal associated therewith. (Matthew 6:17, 18)