Numbers 3:21 (KJV)

And Moses numbered them according to the word of the LORD, as he was commanded.

And these were the sons of Levi by their names; Gershon, and Kohath, and Merari.

And these are the names of the sons of Gershon by their families; Libni, and Shimei.

And the sons of Kohath by their families; Amram, and Izehar, Hebron, and Uzziel.

And the sons of Merari by their families; Mahli, and Mushi. These are the families of the Levites according to the house of their fathers.

Those that were numbered of them, according to the number of all the males, from a month old and upward, even those that were numbered of them were seven thousand and five hundred.

The families of the Gershonites shall pitch behind the tabernacle westward.

And the chief of the house of the father of the Gershonites shall be Eliasaph the son of Lael.

And the charge of the sons of Gershon in the tabernacle of the congregation shall be the tabernacle, and the tent, the covering thereof, and the hanging for the door of the tabernacle of the congregation,

And the hangings of the court, and the curtain for the door of the court, which is by the tabernacle, and by the altar round about, and the cords of it for all the service thereof.