'Freewill Offering' in the Bible

But if the sacrifice of his offering is a vow or a freewill offering, it shall be eaten on the day that he offers his sacrifice, and on the next day that which remains of it may be eaten;

Speak unto Aaron, and to his sons, and unto all the children of Israel, and say unto them, Whatsoever he be of the house of Israel, or of the strangers in Israel, that will offer his oblation for all his vows, and for all his freewill offerings, which they will offer unto the LORD for a burnt offering;

And whosoever offereth a sacrifice of peace offerings unto the LORD to accomplish his vow, or a freewill offering in beeves or sheep, it shall be perfect to be accepted; there shall be no blemish therein.

Either a bullock or a lamb that hath any thing superfluous or lacking in his parts, that mayest thou offer for a freewill offering; but for a vow it shall not be accepted.

Beside the sabbaths of the LORD, and beside your gifts, and beside all your vows, and beside all your freewill offerings, which ye give unto the LORD.