Plato, Laws 895a

καὶ οὕτω δὴ χίλια ἐπὶ μυρίοις γίγνηται τὰ κινηθέντα, μῶν ἀρχή τις αὐτῶν ἔσται τῆς κινήσεως ἁπάσης ἄλλη πλὴν ἡ τῆς αὐτῆς αὑτὴν κινησάσης μεταβολή; κάλλιστα εἶπες, συγχωρητέα τε τούτοις. ἔτι δὴ καὶ τῇδε εἴπωμεν, καὶ ἀποκρινώμεθα πάλιν ἡμῖν αὐτοῖσιν. εἰ σταίη πως τὰ πάντα ὁμοῦ γενόμενα, καθάπερ οἱ πλεῖστοι τῶν τοιούτων τολμῶσι λέγειν, τίνʼ ἄρα ἐν αὐτοῖς ἀνάγκη πρώτην κίνησιν γενέσθαι τῶν εἰρημένων;

will the primary source of all their motions be anything else than the movement of that which has moved itself? Excellently put, and we must assent to your argument. Further, let us question and answer ourselves thus:—Supposing that the Whole of things were to unite and stand still,—as most of these thinkers venture to maintain,—which of the motions mentioned would necessarily arise in it first? That motion, of course, which is self-moving; for it will never be shifted beforehand by another thing,