Plato, Laws 773c

πόλις ὅλη γίγνεται χρήμασίν τε καὶ τρόπων ἤθεσιν· ἐξ ὧν ἃ μὴ βουλόμεθα συμβαίνειν ἡμῖν, καὶ μάλιστα συμβαίνει ταῖς πλείσταις πόλεσι. ταῦτα δὴ διὰ λόγου μὲν νόμῳ προστάττειν, μὴ γαμεῖν πλούσιον πλουσίου, μηδὲ πολλὰ δυνάμενον πράττειν ἄλλου τοιούτου, θάττους δὲ ἤθεσι πρὸς βραδυτέρους καὶ βραδυτέρους πρὸς θάττους ἀναγκάζειν τῇ τῶν γάμων κοινωνίᾳ πορεύεσθαι, πρὸς τῷ γελοῖα εἶναι θυμὸν ἂν ἐγείραι πολλοῖς· οὐ γὰρ ῥᾴδιον ἐννοεῖν ὅτι πόλιν εἶναι

both in wealth and in moral habits; and because of this, the consequences we least desire are those that generally befall most States. To make express enactments about these matters by law—that, for instance, a rich man must not marry into a rich family, nor a man of wide power with a powerful family, or that man of hasty tempers must be obliged to seek alliances with those of slower tempers, and the slow with the hasty—this, besides being ridiculous, would cause widespread resentment; for people do not find it easy to perceive