On the day they were anointed, the LORD commanded that this be given them by the sons of Israel. It is a permanent portion for the generations to come.
Here is the conclusion of these laws concerning the sacrifices, though some of them are afterwards repeated and explained. The are to be considered, 1. As a grant to the priests, Lev 7:35, Lev 7:36. In the day they were ordained to that work and office this provision was made for their comfortable maintenance.
Commenting on Leviticus 7:35-38
This is the law of the burnt offering,.... As delivered, Lev 6:9, of the meat offering; as in Lev 6:14, and of the sin offering; as in Lev 6:25, and of the trespass offering; as in Lev 7:1, and of the consecrations; of Aaron and his sons to the priest's office, as in Lev 6:20, and of the sacrifice of the peace offerings; as in...
In the day that he anointed them - See Clarke's note on Exo 40:15.