Plato, Letters 332d

αὐτῷ συνεβεβήκει οὕτως, ἀνομιλήτῳ μὲν παιδείας, ἀνομιλήτῳ δὲ συνουσιῶν τῶν προσηκουσῶν γεγονέναι, πρῶτον ἔπειτα ταύτῃ ὁρμήσαντα φίλους ἄλλους αὑτῷ τῶν οἰκείων ἅμα καὶ ἡλικιωτῶν καὶ συμφώνους πρὸς ἀρετὴν κτήσασθαι, μάλιστα δʼ αὐτὸν αὑτῷ, τούτου γὰρ αὐτὸν θαυμαστῶς ἐνδεᾶ γεγονέναι, λέγοντες οὐκ ἐναργῶς οὕτως—οὐ γὰρ ἦν ἀσφαλές —αἰνιττόμενοι δὲ καὶ διαμαχόμενοι τοῖς λόγοις ὡς οὕτω μὲν πᾶς ἀνὴρ αὑτόν τε καὶ ἐκείνους ὧν ἂν ἡγεμὼν γίγνηται σώσει,

to leave him unprovided with education and unprovided with suitable intercourse, he should, in the first place, make it his aim to acquire other friends for himself from among his kindred and contemporaries who were in harmony about virtue; and to acquire, above all else, this harmony within himself, since in this he was surprisingly deficient. Not that we expressed this openly, for it would not have been safe; but we put it in veiled terms and maintained by argument that this is how every man will save both himself and all those under his leadership, whereas if he does not adopt this course he will bring about entirely opposite results.