Numbers 30:1-2 (NLT)
30 Then Moses summoned the leaders of the tribes of Israel and told them, “This is what the Lord has commanded: 2 A man who makes a vow to the Lord or makes a pledge under oath must never break it. He must do exactly what he said he would do.
Matthew 5:33-37 (NLT)
33 “You have also heard that our ancestors were told, ‘You must not break your vows; you must carry out the vows you make to the Lord.’[n] 34 But I say, do not make any vows! Do not say, ‘By heaven!’ because heaven is God’s throne. 35 And do not say, ‘By the earth!’ because the earth is his footstool. And do not say, ‘By Jerusalem!’ for Jerusalem is the city of the great King. 36 Do not even say, ‘By my head!’ for you can’t turn one hair white or black. 37 Just say a simple, ‘Yes, I will,’ or ‘No, I won’t.’ Anything beyond this is from the evil one.