This is the portion of the food offerings presented to the LORD that were allotted to Aaron and his sons on the day they were presented to serve the LORD as priests.
On the day they were anointed, the LORD commanded that the Israelites give this to them as their perpetual share for the generations to come.
References for Leviticus 7:36
These, then, are the regulations for the burnt offering, the grain offering, the sin offering, the guilt offering, the ordination offering and the fellowship offering,
References for Leviticus 7:37
which the LORD gave Moses at Mount Sinai in the Desert of Sinai on the day he commanded the Israelites to bring their offerings to the LORD.
References for Leviticus 7:38