Exodus 29:26-28

“You shall take the breast of the ram of Aaron’s ordination and wave it for a wave offering before the LORD, and it shall be your portion. And you shall consecrate the breast of the wave offering that is waved and the thigh of the priests’ portion that is contributed from the ram of ordination, from what was Aaron’s and his sons’. It shall be for Aaron and his sons as a perpetual due from the people of Israel, for it is a contribution. It shall be a contribution from the people of Israel from their peace offerings, their contribution to the LORD.