Numbers 4:16, 28, 33

“The appointed duty of Eleazar the son of Aaron the priest is the oil for the light, the sweet incense, the daily grain offering, the anointing oil, the oversight of all the tabernacle, of all that is in it, with the sanctuary and its furnishings.”

This is the service of the families of the sons of Gershon in the tabernacle of meeting. And their duties shall be under the authority of Ithamar the son of Aaron the priest.

This is the service of the families of the sons of Merari, as all their service for the tabernacle of meeting, under the authority of Ithamar the son of Aaron the priest.”