Exodus 29:27-28

27You shall consecrate the breast of the wave offering and the thigh of the 1contribution which was waved and which was 2offered from the ram of 3ordination, from the one which was for Aaron and from the one which was for his sons. 28It shall be for Aaron and his sons as their portion forever from the sons of Israel, for it is 4a contribution; and it shall be 5a contribution from the sons of Israel from the sacrifices of their peace offerings, their 6contribution to the Lord.