Eternal illumination and the cycle of return
Procopius is distinguishing the completed essential procession of eternal beings from their perpetual procession according to illumination, which cycles back to the one origin.
Those very things that were produced undergo change in their essence, and so they need another production in turn. But the procession according to illumination proceeds from there eternally and endlessly: to some as first-given, to others as second-given, and so on in order. The divine radiances are poured out for sharing, in proportion to the ranks, or rather the stations, of each being, down to the last things within them. In this way all things also return, drawn upward to the one origin, and the eternal and endless circle is preserved for them both in their processions and in their returns. But the procession of things subject to generation, corruption, and time has already been completed in its universal aspect.
Greek
αὐτὰ ἐκεῖνα τὰ παραχθέντα, τὴν κατ' οὐσίαν μεταβολὴν ὑπομένοντα, πάλιν ἄλλης
παραγωγῆς δέονται· ἡ δὲ κατ' ἔλλαμψιν, ἀΐδιος ἐκεῖθεν προβαίνει καὶ ἀτελεύτητος,
τοῖς μὲν πρω- τοδότως, τοῖς δὲ δευτεροδότως, καὶ καθεξῆς· τῶν θείων
ἀπαυγασμάτων προχεομένων κατὰ μετάδοσιν, ἀναλόγως ταῖς ἑκάστων τάξεσιν εἴτ'
οὖν στάσεσι, μέχρι καὶ τῶν ἐν ἐκείνοις ἐσχάτων· οὕτω δὲ καὶ πάντα πρὸς τὴν μίαν
ἀρχὴν ἀνατατικῶς ἐπιστρέφει· καὶ ὁ ἀΐδιος τούτοις καὶ ἀτελεύτητος ἔν τε ταῖς
προόδοις καὶ ταῖς ἐπιτροφαῖς κύκλος σώζεται· ἡ δὲ τῶν ὑπὸ γένεσιν καὶ φθορὰν καὶ
χρόνον, κατὰ μὲν τὸ καθόλου, καὶ ἤδη τετέλεσται.