Why did God require sacrifices without defect?


…you must present a male without defect from the cattle, sheep or goats in order that it may be accepted on your behalf. Do not bring anything with a defect, because it will not be accepted on your behalf. When anyone brings from the herd or flock a fellowship offering to the Lord to fulfill a special vow or as a freewill offering, it must be without defect or blemish to be acceptable. Do not offer to the Lord the blind, the injured or the maimed, or anything with warts or festering or running sores. Do not place any of these on the altar as a food offering presented to the Lord. Leviticus 22:19-22
            God required sacrifices without defect as a symbolic gesture toward the ultimate sacrifice that would one day come and take away the sin of the world—Jesus.  Jesus would be the only sacrifice to be without any sin (or defect) to die for all sin.  The animal sacrifices were temporary placeholders, pointing the way to Jesus.