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 18:1
Responsibilities of the Priests
18:1 The Lord said to Aaron, “You and your sons and your tribe with you must bear the iniquity of the sanctuary, and you and your sons with you must bear the iniquity of your priesthood.
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.”