Numbers 4:27-29

American Standard Version

²⁷ At the commandment of Aaron and his sons shall be all the service of the sons of the Gershonites, in all their burden, and in all their service; and ye shall appoint unto them in charge all their burden. ²⁸ This is the service of the families of the sons of the Gershonites in the tent of meeting: and their charge shall be under the hand of Ithamar the son of Aaron the priest.

²⁹ As for the sons of Merari, thou shalt number them by their families, by their fathers’ houses;