Numbers 3:38

3:38 But those who were to camp in front of the tabernacle on the east, in front of the tent of meeting, were Moses, Aaron, and his sons. They were responsible for the needs of the sanctuary and for the needs of the Israelites, but the unauthorized person who approached was to be put to death.

Numbers 18:7

18:7 But you and your sons with you are responsible for your priestly duties, for everything at the altar and within the curtain. And you must serve. I give you the priesthood as a gift for service; but the unauthorized person who approaches must be put to death.”

Numbers 35:25

35:25 The community must deliver the slayer out of the hand of the avenger of blood, and the community must restore him to the town of refuge to which he fled, and he must live there until the death of the high priest, who was anointed with the consecrated oil.