Numbers 4:16, 27

“Eleazar son of Aaron, the priest, is to have charge of the oil for the light, the fragrant incense, the regular grain offering and the anointing oil. He is to be in charge of the entire tabernacle and everything in it, including its holy furnishings and articles.”

All their service, whether carrying or doing other work, is to be done under the direction of Aaron and his sons. You shall assign to them as their responsibility all they are to carry.