Leviticus 7:33 (KJV)

And the priest shall burn the fat upon the altar: but the breast shall be Aaron’s and his sons’.

And the right shoulder shall ye give unto the priest for an heave offering of the sacrifices of your peace offerings.

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

For the wave breast and the heave shoulder have I taken of the children of Israel from off the sacrifices of their peace offerings, and have given them unto Aaron the priest and unto his sons by a statute for ever from among the children of Israel.

This is the portion of the anointing of Aaron, and of the anointing of his sons, out of the offerings of the Lord made by fire, in the day when he presented them to minister unto the Lord in the priest’s office;