Leviticus 22:21

To accomplish a vow It was not unusual with them to make such a vow when they undertook a journey, went to sea, were sick, or in any danger. It shall be perfect That sacrifice was accounted perfect which wanted none of its parts, nor had any defect in any of them; so that perfect here is the same as without blemish, Leviticus 22:19. The design of this law was still to remind them that they ought to offer to God the most excellent of every thing in its kind, and to guard the worship of God from falling into contempt, as it might have done, had they been allowed to offer to their Maker what men despised, Malachi 1:8. It served also to keep up a due distinction between things sacred and things common, for these same animals which were unfit to be offered to God might be used for common food.