Plato, Letters 328c

περὶ νόμων τε καὶ πολιτείας ἀποτελεῖν ἐγχειρήσοι, καὶ νῦν πειρατέον εἶναι· πείσας γὰρ ἕνα μόνον ἱκανῶς πάντα ἐξειργασμένος ἐσοίμην ἀγαθά. ταύτῃ μὲν δὴ τῇ διανοίᾳ τε καὶ τόλμῃ ἀπῆρα οἴκοθεν, οὐχ ᾗ τινες ἐδόξαζον, ἀλλʼ αἰσχυνόμενος μὲν ἐμαυτὸν τὸ μέγιστον, μὴ δόξαιμί ποτε ἐμαυτῷ παντάπασι λόγος μόνον ἀτεχνῶς εἶναι τίς, ἔργου δὲ οὐδενὸς ἄν ποτε ἑκὼν ἀνθάψασθαι, κινδυνεύσειν δὲ προδοῦναι πρῶτον

concerning laws and government, now was the time to undertake it; for should I succeed in convincing one single person sufficiently I should have brought to pass all manner of good. Holding this view and in this spirit of adventure it was that I set out from home,—not in the spirit which some have supposed, but dreading self-reproach most of all, lest haply I should seem to myself to be utterly and absolutely nothing more than a mere voice and never to undertake willingly any action, and now to be in danger of proving false, in the first instance, to my friendship