Numbers 18:6-7 ▼

6 I myself have chosen your fellow Levites from among the Israelites to be your special assistants. They are a gift to you, dedicated to the LORD for service in the Tabernacle.

7 But you and your sons, the priests, must personally handle all the priestly rituals associated with the altar and with everything behind the inner curtain. I am giving you the priesthood as your special privilege of service. Any unauthorized person who comes too near the sanctuary will be put to death.”