Numbers 18:4
They must join with you, and they will be responsible for the care of the tent of meeting, for all the service of the tent, but no unauthorized person may approach you.
Numbers 1:51
Whenever the tabernacle is to move, the Levites must take it down, and whenever the tabernacle is to be reassembled, the Levites must set it up. Any unauthorized person who approaches it must be killed.
Numbers 3:10
So you are to appoint Aaron and his sons, and they will be responsible for their priesthood; but the unauthorized person who comes near must be put to death."
1 Samuel 6:19
But the Lord struck down some of the people of Beth Shemesh because they had looked into the ark of the Lord; he struck down 50,070 of the men. The people grieved because the Lord had struck the people with a hard blow.
2 Samuel 6:6-7
When they arrived at the threshing floor of Nacon, Uzzah reached out and grabbed hold of the ark of God, because the oxen stumbled.