Ecclesiastes 5:2-5

2Do not be hasty with your mouth [speaking careless words or vows] or impulsive in thought to bring up a matter before God. For God is in heaven and you are on earth; therefore let your words be few.

3For the dream comes through much effort, and the voice of the fool through many words.

4When you make a vow or a pledge to God, do not put off paying it; for God takes no pleasure in fools [who thoughtlessly mock Him]. Pay what you vow.

5It is better that you should not vow than that you should vow and not pay.