The sole fast required by the law of Moses was that of the great Day of Atonement (q.v.), Leviticus 23:26-32 . It is called "the fast" ( Acts 27:9 ).
The only other mention of a periodical fast in the Old Testament is in Zechariah 7:1-7 ; 8:19 , from which it appears that during their captivity the Jews observed four annual fasts.
There was in addition to these the fast appointed by ( Esther 4:16 ).
Public national fasts on account of sin or to supplicate divine favour were sometimes held.
There were also local fasts.
There are many instances of private occasional fasting ( 1 Samuel 1:7 : 20:34 ; 2 Sam 3:35 ; 12:16 ; 1 Kings 21:27 ; Ezra 10:6 ; Nehemiah 1:4 ; Daniel 10:2 Daniel 10:3 ). Moses fasted forty days ( Exodus 24:18 ; 34:28 ), and so also did Elijah ( 1 Kings 19:8 ). Our Lord fasted forty days in the wilderness ( Matthew 4:2 ).
In the lapse of time the practice of fasting was lamentably abused ( Isaiah 58:4 ; Jeremiah 14:12 ; Zechariah 7:5 ). Our Lord rebuked the Pharisees for their hypocritical pretences in fasting ( Matthew 6:16 ). He himself appointed no fast. The early Christians, however, observed the ordinary fasts according to the law of their fathers ( Acts 13:3 ; 14:23 ; 2 co 6:5 ).
Abstaining from food.Moreover when ye FAST, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to FAST. Verily I say unto you, They have their reward. But thou, when thou FASTEST, anoint thine head, and wash thy face; that thou appear not unto men to FAST, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly. ( Matthew 6:16-18 )