Numbers 4:16, 27

“Now the responsibility of Eleazar the son of Aaron the priest is the oil for the light, the fragrant incense, the continual grain offering, and the anointing oil—the responsibility of all the tabernacle and everything that is in it, with the sanctuary and its furnishings.”

All the service of the sons of the Gershonites, that is, all their loads and all their work, shall be performed at the command of Aaron and his sons; and you shall assign to them as a duty all their loads.