Plato, Letters 328e

καθιστάναι ἑκάστοτε· ὧν ἐνδείᾳ κατὰ τὸ σὸν μέρος νῦν ἐγὼ καταλιπὼν Συρακούσας ἐνθάδε πάρειμι. καὶ τὸ μὲν ἐμὸν ἔλαττον ὄνειδός σοι φέρει· φιλοσοφία δέ, ἣν ἐγκωμιάζεις ἀεὶ καὶ ἀτίμως φῂς ὑπὸ τῶν λοιπῶν ἀνθρώπων φέρεσθαι, πῶς οὐ προδέδοται τὰ νῦν μετʼ ἐμοῦ μέρος ὅσον ἐπὶ σοὶ γέγονεν;

and comradeship. And it is because you have left me destitute of these that I have now quitted Syracuse and come hither. My condition, however, casts a lesser reproach on you; but as for Philosophy, which you are always belauding, and saying that she is treated with ignominy by the rest of mankind, surely, so far as it depends on you, she too is now betrayed