When you make a vow to God, do not delay in fulfilling it.1 He has no pleasure in fools; fulfill your vow.2
References for Ecclesiastes 5:4
It is better not to vow than to make a vow and not fulfill it.3
References for Ecclesiastes 5:5
Do 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?