Plato, Laws 690c

ἄρχειν. καίτοι τοῦτό γε, ὦ Πίνδαρε σοφώτατε, σχεδὸν οὐκ ἂν παρὰ φύσιν ἔγωγε φαίην γίγνεσθαι, κατὰ φύσιν δέ, τὴν τοῦ νόμου ἑκόντων ἀρχὴν ἀλλʼ οὐ βίαιον πεφυκυῖαν. ὀρθότατα λέγεις. θεοφιλῆ δέ γε καὶ εὐτυχῆ τινα λέγοντες ἑβδόμην ἀρχήν, εἰς κλῆρόν τινα προάγομεν, καὶ λαχόντα μὲν ἄρχειν, δυσκληροῦντα δὲ ἀπιόντα ἄρχεσθαι τὸ δικαιότατον εἶναί φαμεν. ἀληθέστατα λέγεις.

my most sapient Pindar, this is a thing that I, for one, would hardly assert to be against nature, but rather according thereto—the natural rule of law, without force, over willing subjects. A very just observation. Heaven’s favour and good-luck mark the seventh form of rule, where we bring a man forward for a casting of lots, and declare that if he gains the lot he will most justly be ruler, but if he fails he shall take his place among the ruled. Very true.