Leviticus 7:33-38 NLT

33 The right thigh must always be given to the priest who offers the blood and the fat of the peace offering.
34 For I have reserved the breast of the special offering and the right thigh of the sacred offering for the priests. It is the permanent right of Aaron and his descendants to share in the peace offerings brought by the people of Israel.
35 This is their rightful share. The special gifts presented to the have been reserved for Aaron and his descendants from the time they were set apart to serve the as priests.
36 On the day they were anointed, the commanded the Israelites to give these portions to the priests as their permanent share from generation to generation.”
37 These are the instructions for the burnt offering, the grain offering, the sin offering, and the guilt offering, as well as the ordination offering and the peace offering.
38 The gave these instructions to Moses on Mount Sinai when he commanded the Israelites to present their offerings to the in the wilderness of Sinai.