Numbers 4:16-20

16Eleazar son of Aaron the priest shall oversee the oil for the light, the fragrant incense, the daily grain offering, and the anointing oil. He has oversight of the entire tabernacle and everything in it, including the holy objects and their utensils.”

17Then the LORD said to Moses and Aaron, 18“Do not allow the Kohathite tribal clans to be cut off from among the Levites. 19In order that they may live and not die when they come near the most holy things, do this for them: Aaron and his sons are to go in and assign each man his task and what he is to carry. 20But the Kohathites are not to go in and look at the holy objects, even for a moment, or they will die.”