Numbers 18:1, 7

The LORD said to Aaron, “You, your sons, and your ancestral family  , will be responsible for iniquity against the sanctuary. You and your sons will be responsible for iniquity involving your priesthood.

But you and your sons will carry out your priestly responsibilities  for everything concerning the altar and for what is inside the curtain, 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.”