Leviticus 7:7-8, 32, 34-35

As the sin offering is, so is the trespass offering: there is one law for them: the priest that maketh atonement therewith shall have it. And the priest that offereth any man's burnt offering, even the priest shall have to himself the skin of the burnt offering which he hath offered.

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

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