Numbers 4:16
And to the office of Eleazar the son of Aaron the priest pertaineth the oil for the light, and the sweet incense, and the daily meat offering, and the anointing oil, and the oversight of all the tabernacle, and of all that therein is, in the sanctuary, and in the vessels
More from Numbers 4
And the LORD spake unto Moses and unto Aaron, saying,
Take the sum of the sons of Kohath from among the sons of Levi, after their families, by the house of their fathers,
From thirty years old and upward even until fifty years old, all that enter into the host, to do the work in the tabernacle of the congregation.
This shall be the service of the sons of Kohath in the tabernacle of the congregation, about the most holy things:
And when the camp setteth forward, Aaron shall come, and his sons, and they shall take down the covering vail, and cover the ark of testimony