Nadab and Abihu died before YHWH when they offered strange fire before YHWH in the wilderness of Sinai, and they had no children. Eleazar and Ithamar ministered in the priest’s office in the presence of Aaron their father.
You and your sons, y’all are to carry out y’all’s priesthood for everything of the altar, and for that within the veil. Y’all must serve. I give the service of the priesthood to y’all as a gift. The stranger who comes near must be put to death.”
Moses spoke to Aaron and his remaining sons, Eleazar and Ithamar, “Y’all are to take the grain offering that is left over from the burnt offerings to YHWH, and y’all are eat it without yeast beside the altar, for it is most holy.
You are to clothe them with belts, Aaron and his sons, and bind headbands on them. They are to have the priesthood by a perpetual statute. You are to consecrate Aaron and his sons.