Plato, Laws 735a

βεβαιότητα ἐν τοῖς τρόποις εἰληφός, τὸ δὲ μαλακώτερον καὶ ἐπιεικείᾳ τινὶ δικαίᾳ χρώμενον—ὅθεν δὴ τοὺς τὰς ἀρχὰς ἐν ταῖς πόλεσιν ἄρξοντας δεῖ διακρίνεσθαί τινα τρόπον ταύτῃ καὶ τοὺς σμικρᾷ παιδείᾳ βασανισθέντας ἑκάστοτε κατὰ λόγον. ἐστὸν γὰρ δὴ δύο πολιτείας εἴδη, τὸ μὲν ἀρχῶν καταστάσεις ἑκάστοις, τὸ δὲ νόμοι ταῖς ἀρχαῖς ἀποδοθέντες.τὸ δὲ πρὸ τούτων ἁπάντων δεῖ διανοεῖσθαι τὰ τοιάδε.

whereas the woof is softer and shows a due degree of flexibility—from this we may see that in some such way we must mark out those who are to hold high offices in the State and those who are to hold low offices, after applying in each case an adequate educational test. For of State organization there are two divisions, of which the one is the appointment of individuals to office, the other the assignment of laws to the offices. But, in truth, before we deal with all these matters we must observe the following.