Here's three instances:
“Speak to Aaron and his sons, and to all the children of Israel, and say to them: ‘Whatever man of the house of Israel, or of the strangers in Israel, who offers his sacrifice for any of his vows or for any of his
freewill offerings, which they offer to the Lord as a burnt offering— . . . And whoever offers a sacrifice of a peace offering to the Lord, to fulfill his vow, or a
freewill offering from the cattle or the sheep, it must be perfect to be accepted; there shall be no defect in it. . . . Either a bull or a lamb that has any limb too long or too short you may offer as a
freewill offering, but for a vow it shall not be accepted. - Leviticus 22:18,21,23
http://www.biblegateway.com/passage/?search=Leviticus22:18,21,23&version=NKJV