Numbers 4:20

“And he shall put the incense on the fire before Yahweh, that the cloud of incense may cover the mercy seat that is on the ark of the testimony, so that he will not die.

“So when the tabernacle is to set out, the Levites shall take it down; and when the tabernacle encamps, the Levites shall set it up. But the layman who comes near shall be put to death.

“When Aaron and his sons have finished covering the holy objects and all the furnishings of the sanctuary, when the camp is to set out, after that the sons of Kohath shall come to carry them, so that they will not touch the holy objects and die. These are the things in the tent of meeting which the sons of Kohath are to carry.

Then the Kohathites set out, carrying the holy objects; and the tabernacle was set up before their arrival.

“And they shall thus keep your responsibility and the responsibility of all the tent, but they shall not come near to the furnishings of the sanctuary and the altar, so that neither they nor you will die.

Then He struck down some of the men of Beth-shemesh because they had looked into the ark of Yahweh. He struck down of all the people, 50,070 men, and the people mourned because Yahweh had struck the people with a great slaughter.

Then they came to the threshing floor of Nacon. And Uzzah reached out toward the ark of God and took hold of it, because the oxen nearly upset it.

And the Levites were numbered from thirty years old and upward, and their number by census of men was 38,000.

“Yet they shall be ministers in My sanctuary, having oversight at the gates of the house and ministering in the house; they shall slaughter the burnt offering and the sacrifice for the people, and they shall stand before them to minister to them.