Numbers 4:27-29

Young's Literal Translation

²⁷ `By the command of Aaron and his sons is all the service of the sons of the Gershonite in all their burden, and in all their service; and ye have laid a charge on them concerning the charge of all their burden.

²⁸ This [is] the service of the families of the sons of the Gershonite in the tent of meeting; and their charge [is] under the hand of Ithamar son of Aaron the priest.

²⁹ `The sons of Merari, by their families, by the house of their fathers, thou dost number them;