This is the family line of Aaron and Moses as it was recorded when the LORD spoke to Moses on Mount Sinai: The names of Aaron’s sons were Nadab (the oldest), Abihu, Eleazar, and Ithamar. These sons of Aaron were anointed and ordained to minister as priests. But Nadab and Abihu died in the LORD’s presence in the wilderness of Sinai when they burned before the LORD the wrong kind of fire, different than he had commanded. Since they had no sons, this left only Eleazar and Ithamar to serve as priests with their father, Aaron.
Then the LORD said to Moses, “Call forward the tribe of Levi, and present them to Aaron the priest to serve as his assistants. They will serve Aaron and the whole community, performing their sacred duties in and around the Tabernacle. They will also maintain all the furnishings of the sacred tent, serving in the Tabernacle on behalf of all the Israelites. Assign the Levites to Aaron and his sons. They have been given from among all the people of Israel to serve as their assistants. Appoint Aaron and his sons to carry out the duties of the priesthood. But any unauthorized person who goes too near the sanctuary must be put to death.”
And the LORD said to Moses, “Look, I have chosen the Levites from among the Israelites to serve as substitutes for all the firstborn sons of the people of Israel. The Levites belong to me, for all the firstborn males are mine. On the day I struck down all the firstborn sons of the Egyptians, I set apart for myself all the firstborn in Israel, both of people and of animals. They are mine; I am the LORD.”
The LORD spoke again to Moses in the wilderness of Sinai. He said, “Record the names of the members of the tribe of Levi by their families and clans. List every male who is one month old or older.” So Moses listed them, just as the LORD had commanded.
Levi had three sons, whose names were Gershon, Kohath, and Merari.
The clans descended from Gershon were named after two of his descendants, Libni and Shimei.
The clans descended from Kohath were named after four of his descendants, Amram, Izhar, Hebron, and Uzziel.
The clans descended from Merari were named after two of his descendants, Mahli and Mushi.
These were the Levite clans, listed according to their family groups.
The descendants of Gershon were composed of the clans descended from Libni and Shimei. There were 7,500 males one month old or older among these Gershonite clans. They were assigned the area to the west of the Tabernacle for their camp. The leader of the Gershonite clans was Eliasaph son of Lael. These two clans were responsible to care for the Tabernacle, including the sacred tent with its layers of coverings, the curtain at its entrance, the curtains of the courtyard that surrounded the Tabernacle and altar, the curtain at the courtyard entrance, the ropes, and all the equipment related to their use.