Plato, Laws 839c

τῇ μὲν ῥᾴστην ἁπασῶν, τῇ δὲ χαλεπωτάτην, πρὸς τὸ τοῦτον τεθέντα ἐμμεῖναι τὸν νόμον. νοῆσαι μὲν γὰρ δὴ ῥᾷστον ὡς δυνατόν τέ ἐστιν καὶ ὅπῃ—φαμὲν γὰρ δὴ καθιερωθὲν τοῦτο ἱκανῶς τὸ νόμιμον πᾶσαν ψυχὴν δουλώσεσθαι καὶ παντάπασιν μετὰ φόβου ποιήσειν πείθεσθαι τοῖς τεθεῖσιν νόμοις—ἀλλὰ γὰρ εἰς τοῦτο προβέβηκε νῦν, ὥστʼ οὐδʼ ἂν τότε γενέσθαι δοκεῖ, καθάπερ τὸ τῶν συσσιτίων ἐπιτήδευμα ἀπιστεῖται μὴ δυνατὸν εἶναι δύνασθαι διὰ βίου πόλιν ὅλην

that I knew of a device to secure the permanence of this law when passed which is at once the easiest of all devices and the hardest. For while it is very easy to perceive that this is possible, and how it is possible—since we affirm that this rule, when duly consecrated, will dominate all souls, and cause them to dread the laws enacted and yield them entire obedience,—yet it has now come to this, that men think that, even so, it is unlikely to come about,—just in the same way as, in the case of the institution of public meals, people refuse to believe that it is possible