Numbers 3:36

3:36 The appointed responsibilities of the Merarites included the frames of the tabernacle, its crossbars, its posts, its sockets, its utensils, plus all the service connected with these things,

Numbers 4:28

4:28 This is the service of the families of the Gershonites concerning the tent of meeting. Their responsibilities will be under the authority of Ithamar son of Aaron the priest.