and the Levitical priests shall never lack a man in my presence to offer burnt offerings, to make grain offerings, and to make sacrifices for all time.
They shall be ministers in my sanctuary, having oversight at the gates of the temple and serving in the temple; they shall slaughter the burnt offering and the sacrifice for the people, and they shall attend on them and serve them.
So bring with you also your brothers of the tribe of Levi, your ancestral tribe, in order that they may be joined to you and serve you while you and your sons with you are in front of the tent of the covenant.
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. Eleazar and Ithamar served as priests in the lifetime of their father Aaron.