'Priestly' in the Bible

You are to appoint Aaron and his sons to carry out their priestly responsibilities, but any unauthorized person who comes near the sanctuary must be put to death.”

But you and your sons will carry out your priestly responsibilities for everything concerning the altar and for what is inside the veil, and you will do that work. I am giving you the work of the priesthood as a gift, but an unauthorized person who comes near the sanctuary will be put to death.”