Deuteronomy 4:23

4:23 Be on guard so that you do not forget the covenant of the Lord your God that he has made with you, and that you do not make an image of any kind, just as he has forbidden you.

Deuteronomy 23:21

23:21 When you make a vow to the Lord your God you must not delay in fulfilling it, for otherwise he will surely hold you accountable as a sinner.