Deuteronomy 23:21 Deut. 23:21
When thou shalt vow a vow unto the LORD thy God, thou shalt not slack to pay it: for the LORD thy God will surely require it of thee; and it would be sin in thee.
Matthew 5:33 Mt. 5:33
Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths:
(Relation)