Plato, Laws 708d

καὶ νομοθετοῦντι καὶ δυσπειθὲς γίγνεται· τὸ δʼ αὖ παντοδαπὸν ἐς ταὐτὸν συνερρυηκὸς γένος ὑπακοῦσαι μέν τινων νόμων καινῶν τάχα ἂν ἐθελήσειε μᾶλλον, τὸ δὲ συμπνεῦσαι, καὶ καθάπερ ἵππων ζεῦγος καθʼ ἕνα εἰς ταὐτόν, τὸ λεγόμενον, συμφυσῆσαι, χρόνου πολλοῦ καὶ παγχάλεπον. ἀλλʼ ὄντως ἐστὶν νομοθεσία καὶ πόλεων οἰκισμοὶ πάντων τελεώτατον πρὸς ἀρετὴν ἀνδρῶν. εἰκός· ὅπῃ δʼ αὖ βλέπων τοῦτʼ εἴρηκας, φράζʼ ἔτι σαφέστερον.

On the other hand, the clan that is formed by fusion of various elements would perhaps be more ready to submit to new laws, but to cause it to share in one spirit and pant (as they say) in unison like a team of horses would be a lengthy task and most difficult. But in truth legislation and the settlement of States are tasks that require men perfect above all other men in goodness. Very probably; but tell us still more clearly the purport of these observations.