Leviticus 7:34-36

34For 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 to Aaron the priest and to his sons by a statute for ever from among the children of Israel.

35This 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 to the LORD in the priest’s office; 36Which the LORD commanded to be given to them by the children of Israel, in the day that he anointed them, by a statute for ever throughout their generations.