Leviticus 7:33-34

³³The one that offereth the blood of the peace-offerings and the fat, among the sons of Aaron, shall have the right shoulder for his part.

³⁴For the breast which hath been waved and the shoulder which hath been lifted up have I taken from the children of Israel from the sacrifices of their peace-offerings; and I have given them unto Aaron the priest and unto his sons as a fixed portion for ever from the children of Israel.