Numbers 18:7

וְאַתָּ֣ה וּבָנֶ֣יךָ אִ֠תְּךָ תִּשְׁמְר֨וּ אֶת־כְּהֻנַּתְכֶ֜ם לְכָל־דְּבַ֧ר הַמִּזְבֵּ֛חַ וּלְמִבֵּ֥ית לַפָּרֹ֖כֶת וַעֲבַדְתֶּ֑ם עֲבֹדַ֣ת מַתָּנָ֗ה אֶתֵּן֙ אֶת־כְּהֻנַּתְכֶ֔ם וְהַזָּ֥ר הַקָּרֵ֖ב יוּמָֽת׃ ס

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.

Greek text from Swete's edition, CC BY-SA 4.0

Mas tú y tus hijos contigo guardaréis vuestro sacerdocio en todo negocio del altar, y del velo adentro, y ministraréis. Yo os he dado en don el servicio de vuestro sacerdocio; y el extraño que se llegare, morirá.

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.” Offerings for Priests and Levites