Deuteronomy 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."
Cross References (ranked by relevance)
I will pay my vows unto the LORD now in the presence of all his people,
Thy vows are upon me, O God: I will render praises unto thee.
Vow, and pay unto the LORD your God: let all that be round about him bring presents unto him that ought to be feared.
And Jacob vowed a vow, saying, If God will be with me, and will keep me in this way that I go, and will give me bread to eat, and raiment to put on,
Thou shalt not bring the hire of a whore, or the price of a dog, into the house of the LORD thy God for any vow: for even both these are abomination unto the LORD thy God.
Then the men feared the LORD exceedingly, and offered a sacrifice unto the LORD, and made vows.
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:
Behold upon the mountains the feet of him that bringeth good tidings, that publisheth peace! O Judah, keep thy solemn feasts, perform thy vows: for the wicked shall no more pass through thee; he is utterly cut off.
But I will sacrifice unto thee with the voice of thanksgiving; I will pay that that I have vowed. Salvation is of the LORD.