Leviticus 22:17-20

17And the Lord spake unto Moses, saying, 18Speak 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; 19Ye shall offer at your own will a male without blemish, of the beeves, of the sheep, or of the goats. 20But whatsoever hath a blemish, that shall ye not offer: for it shall not be acceptable for you.