Plato, Meno 91c

Ἡράκλεις, εὐφήμει, ὦ Σώκρατες. μηδένα τῶν γʼ ἐμῶν μήτε οἰκείων μήτε φίλων, μήτε ἀστὸν μήτε ξένον, τοιαύτη μανία λάβοι, ὥστε παρὰ τούτους ἐλθόντα λωβηθῆναι, ἐπεὶ οὗτοί γε φανερά ἐστι λώβη τε καὶ διαφθορὰ τῶν συγγιγνομένων. πῶς λέγεις, ὦ Ἄνυτε; οὗτοι ἄρα μόνοι τῶν ἀντιποιουμένων τι ἐπίστασθαι εὐεργετεῖν τοσοῦτον τῶν ἄλλων διαφέρουσιν, ὅσον οὐ μόνον οὐκ ὠφελοῦσιν, ὥσπερ οἱ ἄλλοι, ὅτι ἄν τις αὐτοῖς παραδῷ, ἀλλὰ καὶ τὸ ἐναντίον διαφθείρουσιν;

For heaven’s sake hold your tongue, Socrates! May no kinsman or friend of mine, whether of this city or another, be seized with such madness as to let himself be infected with the company of those men; for they are a manifest plague and corruption to those who frequent them. What is this, Anytus? Of all the people who set up to understand how to do us good, do you mean to single out these as conveying not merely no benefit, such as the rest can give, but actually corruption