Fasting in scripture is primarily an extension of prayer. It is only in recent years that it has become a new form of diet or a popularized meditation technique. I will make a few comments on the biblical use of fasting and leave other uses to others.
Prayer and fasting are mentioned together in eleven verses in the Bible.
Here are a couple of examples:
- Matthew 17:20 And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. 21 Howbeit this kind goeth not out but by prayer and fasting.
Acts 14:23 And when they had ordained them elders in every church, and had prayed with fasting, they commended them to the Lord, on whom they believed.
Many scriptures show the strong connection between fasting and prayer. Physically speaking, to fast is to go without food and perhaps without drink. Spiritually speaking, fasting is an intensification of prayer. Therefore, we are to fast when we are greatly troubled about something; when we specifically and earnestly need an answer from God; when we earnestly want to conquer some sin; when we strongly desire to return fully to God.
Fasting is also strongly connected with weeping or mourning. See the following examples out of eight times the words for fasting and weeping occur in the same verses:
- 2 Samuel 12:21 Then said his servants unto him, What thing is this that thou hast done? thou didst fast and weep for the child, while it was alive; but when the child was dead, thou didst rise and eat bread.
- Nehemiah 1:4 And it came to pass, when I heard these words, that I sat down and wept, and mourned certain days, and fasted, and prayed before the God of heaven,
- Psalm 69:10 When I wept, and chastened my soul with fasting, that was to my reproach.
David refers to the humbling of his soul with fasting (Psalm 35:13) and to the chastening of his soul with fasting (Psalm 69:10). In the Bible, one of the synonymns for fasting is the afflicting of the soul.
- Leviticus 16:31 It shall be a sabbath of rest unto you, and ye shall afflict your souls, by a statute for ever.
- Isaiah 58:3 Wherefore have we fasted, say they, and thou seest not? wherefore have we afflicted our soul, and thou takest no knowledge? Behold, in the day of your fast ye find pleasure, and exact all your labours.
Yet, it seemed that fasting became an empty ritual to the Jews. In Isaiah 58:3-7, the Lord reproved the Jews for their meaningless fasts. They found pleasure in the days of their fast (v.3). They fasted for "strife and debate" (v.4). This is not the fast God has chosen. His idea of a righteous fast is to "loose the bands of wickedness" (v.6). It is a telling sign that the Pharisees would fast often and the disciples of Jesus did not fast during His earthly ministry (Matthew 9:14-15). Although Jesus said that they would fast later (and they did), the emphasis on fasting is not as great for New Testament believers as it was for the Jews. It is certainly not to be a formulized ritual. Rather, it is to be practiced from the heart of the individual believer when that believer truly desires to intensify his prayer to God.
The apostles fasted as they sought direction from the Lord. We can take much from their example and do likewise. However, fasting is never commanded in the New Testament. Jesus comes close to telling us to fast when He declares that the faith to move mountains can only come by prayer and fasting (Matthew 17:20-21). However, Paul never commands believers to fast in his epistles (though he did fast). Yet, the New Testament is filled with commands and admonitions to pray. What is the point? I think it is that fasting is a personal practice that is followed as God leads or as the individuals desires to follow after Him.
The Bible gives no instructions concerning how to fast. My best advice for beginners is to go without food (while allowing water) from one evening meal to the next evening meal. Do not make a scene of your fasting or tell anyone who does not need to know (as per Matthew 6:16-18). Spend added time in prayer during this time. Do not expect the ultimate religious experience. Trust God to bless your fast. He will.