"In modern society fasting is seen primarily as a means of protest or threat of self-destruction to put the pressure on higher authorities in order to attain the benefits or claims of the people involved. In other words, it is political in its character. Mahatma Gandhi of India during his fight against British rule, Young Sam Kim of Korea in his protest against the military dictatorship and the comedian Dick Gregory in his struggle against the violation of the civil rights of Native Americans exemplify this.
In the biblical context, however, fasting carries a different meaning. It is not a way of asserting one’s will but a means of opening oneself to the work of God, expressing profound grief over sin and pointing to one’s ultimate dependence on God for all forms of sustenance. Fasting is the act of abstaining from food for spiritual reasons and primarily connotes an openness to divinity and a posture of humility. It involves prayer, grief, penance, seeking guidance and piety. But fasting was widely abused, so it can also carry the imagery of hypocrisy and religious display (Is 58; Mt 6).
One of the most familiar examples of fasting in the Bible is Jesus’ fasting for forty days in the wilderness in order to prepare for his ministry (Mt 4:2). This is obviously the antitype of Moses’ fasting for forty days on Mount Sinai in order to receive the law and guidance in the wilderness (Ex 34:28; Deut 9:9). Jehoshaphat proclaims a fast throughout all Judah to seek the Lord when the sons of Moab and Ammon come to make war against him (2 Chron 20:3). While the church of Antioch fasts and prays (Acts 13:3–4), they are commanded by the Holy Spirit to send Paul and Barnabas as missionaries. Fasting and prayer are frequently associated with people seeking and preparing themselves for divine communications. Through fasting, they can devote themselves to communion with God.
Fasting bears the imagery of grief. When Saul and Jonathan are killed on the battlefield, the inhabitants of Jabesh-gilead bury their bones and fast seven days (1 Sam 31:13). David mourns and weeps and fasts when he hears of the deaths of Saul, Jonathan and Abner (2 Sam 1:12; 3:36). Nehemiah fasts at the news of the fall of Jerusalem (Neh 1:4). When Haman issues the edict to kill the people of Mordecai, the Jews fast, weep and wail for their destiny (Esther 4:3). Fasting is associated with sincere grief and mourning, particularly with the death of the beloved, a sudden calamity and threat of death. It is an expression of deep sorrow and anger.
Fasting carries the imagery of penitence (see Repentance). For example, Ahab, the king of Israel, fasts at Elijah’s threat to destroy his household for having taken Naboth’s vineyard (1 Kings 21:27). He tears his clothes, puts on sackcloth and goes about despondently. Ahab humbles himself before the Lord and seeks his mercy. The Lord sees this and withdraws the evil he had proclaimed against him (v. 29). Israel as a corporate group fasts on the occasion of repentance. Particularly on the Day of Atonement, the people of Israel are commanded to fast in repentance (Lev 16:29, 31; 23:27, 29, 32). At the time of Nehemiah the people of Israel assemble in sackcloth with dirt on them and fast. They confess their sins and the iniquities of their fathers (Neh 9:1–3; 1 Sam 7:6; 2 Sam 12:16). Fasting is practiced during the course of repentance of sins as a symbol of humility and as a means of seeking the mercy of the Lord.
Fasting is used as a means of piety. The psalmist confesses that he humbled his soul with fasting (Ps 35:13) and that when he wept in his soul with fasting, he was publicly insulted (Ps 69:10). In the NT, Anna, a prophetess and a widow to the age of eighty-four, never leaves the temple, serving night and day with fasting and prayer (Lk 2:37). The disciples of John the Baptist and the Pharisees fast regularly. Particularly, the Pharisees are reported to fast twice a week (Lk 18:12; see extrabiblical sources Didache; 8:1; Psalms of Solomon 3:8). Fasting is conducted for the sake of personal piety and spiritual discipline.
The imagery of piety goes together with fasting; however, fasting also bears the opposite imagery, that of hypocrisy. Isaiah 58:3–6 shows that the fasting of the Israelites as a religious devotion does not match their behavior toward their neighbors. They do evil in the sight of the Lord even during the period of fasting. They only fast to display their godliness to men and gain their admiration. They do not do it for the glory of God. Therefore the Lord proclaims that he will not accept them (Jer 14:2). The same phenomenon can be observed in the NT. The Pharisees disfigure their faces in order that their fasting may be seen by men and are exposed for their hypocrisy by Jesus, who advises them to anoint their heads and wash their faces so that their piety and devotion might be directed only to God (Mt 6:16–17). Fasting itself is not condemned, but if it is conducted as a means of seeking self-glory, it is an image of hypocrisy.
Generally, fasting does not carry positive and bright imagery. The Hebrew expression for fasting, “afflicting the soul,” fits well with the imagery of disfiguring the face, weeping, lying on the ground, putting ashes on the head and putting on sackcloth."
-Ryken, Leland ; Wilhoit, Jim ; Longman, Tremper ; Duriez, Colin ; Penney, Douglas ; Reid, Daniel G.: Dictionary of Biblical Imagery. electronic ed. Downers Grove, IL : InterVarsity Press, 2000, c1998, S. 273