Numbers 18:4
They shall join you and attend to the duties of the Tent of Meeting—all the service of the tent—and no stranger [no layman, anyone who is not a Levite] may approach you [and your sons].
Numbers 1:51
When the tabernacle is to go forward, the Levites shall take it down; and when the tabernacle is to [be set up for] camp, the Levites shall set it up. But the layman (non-Levite) who approaches the tabernacle shall be put to death.
Numbers 3:10
So you shall appoint Aaron and his sons, and they shall observe and attend to their priesthood; but the layman (non-Levite) who approaches [the holy things] shall be put to death.”
1 Samuel 6:19
The Lord struck down some of the men of Beth-shemesh because they had looked into the ark of the Lord. He struck down 50,070 men among the people, and the people mourned because the Lord had struck the people with a great slaughter.
2 Samuel 6:6-7
When they came to Nacon’s threshing floor, Uzzah reached out [with his hand] to the ark of God and took hold of it, because the oxen [stumbled and] nearly overturned it.