Offerings: Vow

If, however, the sacrifice he offers is a vow or a freewill offering, it shall be eaten on the day he presents his sacrifice, but the remainder may be eaten on the next day.

But any meat of the sacrifice remaining until the third day must be burned up.

Then the LORD said to Moses, …

If you make a vow to the LORD your God, do not be slow to keep it, because He will surely require it of you, and you will be guilty of sin. …