and you shall gird them with girdles and bind caps on them; and the priesthood shall be theirs by a perpetual statute. Thus you shall ordain Aaron and his sons.
And Moses said to Aaron and to Eleazar and Ithamar, his sons who were left, “Take the cereal offering that remains of the offerings by fire to the Lord, and eat it unleavened beside the altar, for it is most holy;
And you and your sons with you shall attend to your priesthood for all that concerns the altar and that is within the veil; and you shall serve. I give your priesthood as a gift, and any one else who comes near shall be put to death.”
But Nadab and Abihu died before the Lord when they offered unholy fire before the Lord in the wilderness of Sinai; and they had no children. So Eleazar and Ithamar served as priests in the lifetime of Aaron their father.