Here "they" refers to any member of the tribe of Levi who comes "near to anything in the sanctuary;" the word "you" is plural and refers to both Aaron and the rest of the Levites who are serving in approved roles. (See: [[rc://en/ta/man/translate/figs-pronouns]])
Possible meanings are 1) this represents God being extremely angry with his people. AT: "so that I do not become very angry with the people of Israel again" or 2) this represents God punishing them because of his anger. AT: "so that I do not punish the people of Israel again" (See: [[rc://en/ta/man/translate/figs-metonymy]])