LXX Deut 10:8

ἐν ἐκείνῳ τῷ καιρῷ διέστειλεν Κύριος τὴν φυλὴν τὴν Λευεὶ αἴρειν τὴν κιβωτὸν τῆς διαθήκης Κυρίου, παρεστάναι ἔναντι κυρίου, λειτουργεῖν καὶ ἐπεύχεσθαι ἐπὶ τῷ ὀνόματι αὐτοῦ ἕως τῆς ἡμέρας ταύτης.

At that time the LORD set apart the tribe of Levi to carry the ark of the covenant of the LORD, to stand before the LORD to serve Him, and to pronounce blessings in His name, as they do to this day.