Numbers 18:3

3 They will report to you as they go about their duties related to the Tent, but they must not have anything to do with the holy things of the Altar under penalty of death - both they and you will die!

Numbers 18:3 Meaning and Commentary

Numbers 18:3

And they shall keep thy charge, and the charge of all the
tabernacle
That is, the Levites, whatever Aaron and his sons, the priests, should charge them to do, or commit to their care and charge, that they should observe; as to watch and keep out all unfit persons, to take down and set up the tabernacle when needful only they shall not come nigh the vessels of the sanctuary;
as the ark and mercy seat in the holy of holies, the shewbread table, and candlestick in the holy place; wherefore when these were removed from place to place in journeying, they were covered, that they might not touch them as they carried them: and the altar;
both of incense and burnt offering, on neither of which might they offer: that neither they nor you also die:
the priests for suffering them to meddle with things that did not belong to them, and the Levites for intruding themselves.

Numbers 18:3 In-Context

1 God said to Aaron, "You and your sons, along with your father's family, are responsible for taking care of sins having to do with the Sanctuary; you and your sons are also responsible for sins involving the priesthood.

2 So enlist your brothers of the tribe of Levi to join you and assist you and your sons in your duties in the Tent of Testimony.

3 They will report to you as they go about their duties related to the Tent, but they must not have anything to do with the holy things of the Altar under penalty of death - both they and you will die!

4 They are to work with you in taking care of the Tent of Meeting, whatever work is involved in the Tent. Outsiders are not allowed to help you.

5 "Your job is to take care of the Sanctuary and the Altar so that there will be no more outbreaks of anger on the People of Israel.