Plato, Laws 648b

μὲν τῶν πολιτῶν ἆρʼ ἂν δέξαιο βάσανον δυνατὸς εἶναι λαμβάνειν ἀνδρείας τε πέρι καὶ δειλίας; φαίη που πᾶς ἂν δῆλον ὅτι. τί δέ; μετʼ ἀσφαλείας καὶ ἄνευ κινδύνων μεγάλων ἢ μετὰ τῶν ἐναντίων; καὶ τοῦτο μετὰ τῆς ἀσφαλείας συνομολογήσει πᾶς. χρῷο δʼ ἂν εἰς τοὺς φόβους τούτους ἄγων καὶ ἐλέγχων ἐν τοῖς παθήμασιν, ὥστε ἀναγκάζειν ἄφοβον γίγνεσθαι,

or anyone else, would not your first desire be to have a test of courage and of cowardice which you might apply to your citizens? Obviously everyone of them would say Yes. And would you desire a test that was safe and free from serious risks, or the reverse? All will agree, also, that the test must be safe. And would you utilize the test by bringing men into these fears and proving them while thus affected, so as to compel them to become fearless; employing exhortations admonitions and rewards,—