Plato, Letters 359b

τῆς ἀρχῆς ταύτης, γένοιτʼ ἄν· εἰ δʼ ἐπὶ τὸ παιδεῦσαι δεῖ τινος, οὔτε ὁ παιδεύσων οὔτε οἱ παιδευθησόμενοι, ὡς ἐγὼ οἶμαι, εἰσὶν ὑμῖν, ἀλλὰ τὸ λοιπὸν τοῖς θεοῖς εὔχεσθε. καὶ γὰρ σχεδόν τι καὶ αἱ ἔμπροσθεν πόλεις οὕτω κατεσκευάσθησαν, καὶ ἔπειτα εὖ ᾤκησαν, ὑπὸ συμβάσεων πραγμάτων μεγάλων καὶ κατὰ πόλεμον καὶ κατὰ τὰς ἄλλας πράξεις γενομένων, ὅταν ἐν τοιούτοις καιροῖς ἀνὴρ καλός τε καὶ ἀγαθὸς ἐγγένηται μεγάλην δύναμιν ἔχων· τὸ δʼ ἔμπροσθεν

If, however, you require someone to train them, you do not, in my opinion, possess either the trainer or the pupils to be trained; so it only remains for you to pray to the gods. For, in truth, the earlier States also were mostly organized in this way; and they came to have a good constitution at a later date, as a result of their being confronted with grave troubles, either through war or other difficulties, whenever there arose in their midst at such a crisis a man of noble character in possession of great power. So it is both right and necessary that you should at first be eager for these results,