Plato, Letters 317d

ὅσῳπερ ἂν μείζους ὦσιν, τοσούτῳ πλείους καὶ μείζους τοὺς διαβάλλοντας καὶ πρὸς ἡδονὴν μετὰ αἰσχρᾶς βλάβης ὁμιλοῦντας τρεφούσας, οὗ κακὸν οὐδὲν μεῖζον γεννᾷ πλοῦτός τε καὶ ἡ τῆς ἄλλης ἐξουσίας δύναμις—ὅμως δʼ οὖν πάντα ταῦτα χαίρειν ἐάσας ἦλθον, διανοηθεὶς ὡς οὐδένα δεῖ τῶν ἐμῶν φίλων ἐμὲ αἰτιᾶσθαι ὡς διὰ τὴν ἐμὴν ῥᾳθυμίαν τὰ σφέτερα

the greater it is, the greater and more numerous are the slanderers it breeds and the hordes of parasites and wastrels—than which there is no greater evil generated by wealth or by the other privileges of power. Notwithstanding, I put aside all these considerations and went, resolving that none of my friends should lay it to my charge that owing to my lack of energy all their fortunes were ruined when they might have been saved from ruin.