But Aaron and his sons offered on the altar of burnt offering, and on the altar of incense, for all the work of the most holy place, and to make atonement for Israel, according to all that Moses the servant of God had commanded.
God had given the special privilege of being priests to Aaron and his sons as a gracious blessing. Normally the first-born son acted as priest of the family in the ancient Near East. This was one of the privileges of the birthright. Reuben had forfeited this, too, by his sin.