Facing death, even hardened atheists are known to pray. Throughout human history, when men have found themselves in dire straits they have prayed for deliverance and made vows to God, promising to do something for God if He rescued them. The Old Testament gives a number of examples of men making vows in such circumstances. Jacob, fleeing from his brother, offered to tithe his goods if God brought him home safely (Genesis 28:20ff). Israel, after suffering defeated by the Canaanites, vowed the enemy cities to total destruction (Numbers 21:2). Jonah made vows in the belly of the fish (Jonah 2:9).
Vows are made in the heat of the moment. In retrospect, when the crisis is over, they may well seem foolish and unnecessary, and the person who made the vow may be tempted to forget it or only fulfill it partially.
Leviticus chapter 27 is all about vows. It also tells what happens when one doesn’t keep his vows. It may only be a penalty. The real lesson to take away from this study is to keep your vows to God and man.