Fasting, similar to other actions in life, has specific purposes and appointed times. The Bible offers various reasons why people might fast: an immediate need in prayer (2 Samuel 12:16), a need to loosen the bands of wickedness or undo heavy burdens (Isaiah 58:6), during times of elevated conflict or duty in service (Matthew 17:21; Acts 13:3), as a symbol of mourning (2 Samuel 1:12), and as an outward manifestation of true repentance (Jonah 3:5). This list is not exhaustive, but simply demonstrates that God’s people have many good reasons for fasting. Even if none of these circumstances surfaces in our lives, we should fast because we know that the Lord expects us to do so.
Scripturally speaking, a vow involves a solemn promise made to another individual or to God Himself. In our passage, vow is used both as a verb and a noun. Vowing a vow is analogous to someone promising a promise. Men are to keep their word by keeping their promises; or, in other words, men are to be faithfully dependable. When a man makes a promise to God or to another person, he should do everything within his power to keep that promise. The Bible warns against a man allowing his mouth to cause his flesh to sin by making promises with no intention of keeping them. Those who vow a vow to the Lord and fail to perform it are called “fools” and the Lord “hath no pleasure in fools.” Before making any promise, one should first count the cost to determine whether or not making the vow will simply cause him to sin.
