LXX Num 18:7

καὶ σὺ καὶ οἱ υἱοί σου μετὰ σοῦ διατηρήσετε τὴν ἱερατίαν ὑμῶν, κότα πάντα τρόπον τοῦ θυσιαστηρίου καὶ τὸ ἔνδοθεν τοῦ καταπετάσματος, καὶ λειτουργήσετε τὰς λειτουργίας δόμα τῆς ἱερατίας ὑμῶν· καὶ ὁ ἀλλογενὴς ὁ προσπορευόμενος ἀποθανεῖται.

But only you and your sons shall attend to your priesthood for everything concerning the altar and what is inside the veil, and you are to perform that service. I am giving you the work of the priesthood as a gift, but any outsider who comes near the sanctuary must be put to death.”