Nadab and Abihu died before Yahweh, when they offered strange fire before Yahweh, 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.
"Behold, I have taken the Levites from among the children of Israel instead of all the firstborn who open the womb among the children of Israel; and the Levites shall be mine:
for all the firstborn are mine. On the day that I struck down all the firstborn in the land of Egypt I made holy to me all the firstborn in Israel, both man and animal. They shall be mine. I am Yahweh."
Those who were numbered of them, according to the number of all the males, from a month old and upward, even those who were numbered of them were seven thousand five hundred.
The charge of the sons of Gershon in the Tent of Meeting shall be the tabernacle, and the tent, its covering, and the screen for the door of the Tent of Meeting,
and the hangings of the court, and the screen for the door of the court, which is by the tabernacle, and around the altar, and its cords for all of its service.
Of Kohath was the family of the Amramites, and the family of the Izharites, and the family of the Hebronites, and the family of the Uzzielites: these are the families of the Kohathites.
Their charge shall be the ark, the table, the lamp stand, the altars, the vessels of the sanctuary with which they minister, and the screen, and all its service.
Those who encamp before the tabernacle eastward, in front of the Tent of Meeting toward the sunrise, shall be Moses, and Aaron and his sons, keeping the charge of the sanctuary for the charge of the children of Israel. The stranger who comes near shall be put to death.
All who were numbered of the Levites, whom Moses and Aaron numbered at the commandment of Yahweh, by their families, all the males from a month old and upward, were twenty-two thousand.
You shall take the Levites for me (I am Yahweh) instead of all the firstborn among the children of Israel; and the cattle of the Levites instead of all the firstborn among the cattle of the children of Israel."
All the firstborn males according to the number of names, from a month old and upward, of those who were numbered of them, were twenty-two thousand two hundred seventy-three.
"Take the Levites instead of all the firstborn among the children of Israel, and the cattle of the Levites instead of their cattle; and the Levites shall be mine. I am Yahweh.