Leviticus 7:28-36

The LORD said to Moses, “Tell the people of Israel: ‘If someone brings a fellowship offering to the LORD, he must give part of it as his sacrifice to the LORD. He must carry that part of the gift in his own hands as an offering made by fire to the LORD. He must bring the fat and the breast of the animal to the priest, to be presented to the LORD as the priests’ share. Then the priest must burn the fat on the altar, but the breast of the animal will belong to Aaron and the priests. You must also give the right thigh from the fellowship offering to the priest as a gift; it will belong to the priest who offers the blood and fat of the fellowship offering. I have taken the breast and the thigh from the fellowship offerings of the Israelites, and I have given these parts to Aaron and the priests as their share for all time from the Israelites.’ ” This is the portion that belongs to Aaron and his sons from the offerings made by fire to the LORD. They were given this share on the day they were presented to the LORD as priests. On the day the LORD appointed the priests, he commanded Israel to give this share to them, and it is to be given to the priests as their share from now on.