Leviticus 7:33-34

³³He that of Aaron’s sons offereth the blood, and the inner fatness, shall have also the right shoulder in his portion.

³⁴For I have taken from the sons of Israel the breast of raising, and the shoulder of separating, of their peace-able sacrifices, and I have given those to Aaron the priest and to his sons, by everlasting law, of all the people of Israel.