Ecclesiastes 5:4-6

4When you make a vow to God, do not delay to fulfill it. He has no pleasure in fools; fulfill your vow. 5It is better not to make a vow than to make one and not fulfill it. 6Do not let your mouth lead you into sin. And do not protest to the temple messenger, “My vow was a mistake.” Why should God be angry at what you say and destroy the work of your hands?