Numbers 18:3-5

3And they shall thus attend to your obligation and the obligation of all the tent, but 1they shall not come near to the furnishings of the sanctuary and 2the altar, or both they and you will die.

4They shall be joined with you and attend to the obligations of the tent of meeting, for all the service of the tent; but an 3outsider may not come near you.

5So you shall attend to the 4obligations of the sanctuary and the obligations of the altar, 5so that there will no longer be wrath on the sons of Israel.