Charles Ellicott Commentary Leviticus 6:17

"It shall not be baken with leaven. I have given it as their portion of my offerings made by fire; it is most holy, as the sin-offering, and as the trespass-offering." — Leviticus 6:17 (ASV)

I have given it unto them for their portion. —It was ordained that those who ministered at the altar should live of the altar; hence the priests had no portion or inheritance in the land.