Leviticus 6:16-20

And the remainder thereof shall Aaron and his sons eat: with unleavened bread shall it be eaten in the holy place; in the court of the tabernacle of the congregation they shall eat it.

It shall not be baken with leaven. I have given it unto them for their portion of my offerings made by fire; it is most holy, as is the sin offering, and as the trespass offering.

All the males among the children of Aaron shall eat of it. It shall be a statute for ever in your generations concerning the offerings of the LORD made by fire: every one that toucheth them shall be holy.

And the LORD spake unto Moses, saying,

This is the offering of Aaron and of his sons, which they shall offer unto the LORD in the day when he is anointed; the tenth part of an ephah of fine flour for a meat offering perpetual, half of it in the morning, and half thereof at night.