Fast

Fasting (tsom in Hebrew; nesteia in Greek) is the voluntary abstention from food and sometimes drink as a religious act of humiliation, mourning, petition, or consecration. The Mosaic law mandated only a single annual fast — the Day of Atonement (Leviticus 23:26-32), referred to in Acts 27:9 simply as "the fast." However, additional fasts arose throughout Israelite history in response to calamity, national crisis, and repentance (Joel 1:14; 2:15; Zechariah 7–8 records four commemorative fasts).

The prophets challenged fasting that was divorced from justice and genuine repentance (Isaiah 58:3-7; Zechariah 7:5), insisting that God does not desire external religious performance but the broken and contrite heart. Jesus in the Sermon on the Mount assumes his disciples will fast but instructs them to do so without ostentation (Matthew 6:16-18). After the resurrection, fasting appears as a practice associated with prayer in decisive moments of church discernment and mission (Acts 13:2-3; 14:23).