Numbers 4:16-20

16“Eleazar son of Aaron the priest will be responsible for the oil of the lampstand, the fragrant incense, the daily grain offering, and the anointing oil. In fact, Eleazar will be responsible for the entire Tabernacle and everything in it, including the sanctuary and its furnishings.”

17Then the Lord said to Moses and Aaron,

18“Do not let the Kohathite clans be destroyed from among the Levites!

19This is what you must do so they will live and not die when they approach the most sacred objects. Aaron and his sons must always go in with them and assign a specific duty or load to each person.

20The Kohathites must never enter the sanctuary to look at the sacred objects for even a moment, or they will die.”