Plato, Laws 757a

δοῦλοι γὰρ ἂν καὶ δεσπόται οὐκ ἄν ποτε γένοιντο φίλοι, οὐδὲ ἐν ἴσαις τιμαῖς διαγορευόμενοι φαῦλοι καὶ σπουδαῖοι—τοῖς γὰρ ἀνίσοις τὰ ἴσα ἄνισα γίγνοιτʼ ἄν, εἰ μὴ τυγχάνοι τοῦ μέτρου—διὰ γὰρ ἀμφότερα ταῦτα στάσεων αἱ πολιτεῖαι πληροῦνται. παλαιὸς γὰρ λόγος ἀληθὴς ὤν, ὡς ἰσότης φιλότητα ἀπεργάζεται, μάλα μὲν ὀρθῶς εἴρηται καὶ ἐμμελῶς· ἥτις δʼ ἐστί ποτε ἰσότης ἡ τοῦτο αὐτὸ δυναμένη, διὰ τὸ μὴ

be friends with masters, nor bad men with good, even when they occupy equal positions—for when equality is given to unequal things, the resultant will be unequal, unless due measure is applied; and it is because of these two conditions that political organizations are filled with feuds. There is an old and true saying that equality produces amity, which is right well and fitly spoken; but what the equality is which is capable of doing this is a very troublesome question, since it is very far from being clear.