Vows were Made in Reference to Offering Sacrifices

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.

“Speak to Aaron and his sons and all the Israelites and tell them, ‘Any man of the house of Israel or any foreign resident who presents a gift for a burnt offering to the LORD, whether to fulfill a vow or as a freewill offering,

You are not to present to the LORD any animal that is blind, injured, or maimed, or anything with a running sore, a festering rash, or a scab; you must not put any of these on the altar as a food offering to the LORD.

…and you present a food offering to the LORD from the herd or flock to produce a pleasing aroma to the LORD—either a burnt offering or a sacrifice, for a special vow or freewill offering or appointed feast—