Ecclesiastes 5:4-7

4When you make a vow to God, do not delay in fulfilling it, because He takes no pleasure in fools. Fulfill your vow. 5It is better not to vow than to make a vow and not fulfill it.

6Do not let your mouth cause your flesh to sin, and do not tell the messenger1 that your vow was a mistake. Why should God be angry with your words and destroy the work of your hands? 7For as many dreams bring futility, so do many words. Therefore, fear God.