Numbers 18:3-5

Revised Standard Version

³ They shall attend you and attend to all duties of the tent; but shall not come near to the vessels of the sanctuary or to the altar, lest they, and you, die. ⁴ They shall join you, and attend to the tent of meeting, for all the service of the tent; and no one else shall come near you. ⁵ And you shall attend to the duties of the sanctuary and the duties of the altar, that there be wrath no more upon the people of Israel.