Plato, Laws 701c

πρὸς αὐτῷ δὲ ἤδη τῷ τέλει ὅρκων καὶ πίστεων καὶ τὸ παράπαν θεῶν μὴ φροντίζειν, τὴν λεγομένην παλαιὰν Τιτανικὴν φύσιν ἐπιδεικνῦσι καὶ μιμουμένοις, ἐπὶ τὰ αὐτὰ πάλιν ἐκεῖνα ἀφικομένους, χαλεπὸν αἰῶνα διάγοντας μὴ λῆξαί ποτε κακῶν. τίνος δὴ καὶ ταῦθʼ ἡμῖν αὖ χάριν ἐλέχθη; δεῖν φαίνεται ἔμοιγε οἷόνπερ ἵππον τὸν λόγον ἑκάστοτε ἀναλαμβάνειν, καὶ μὴ καθάπερ ἀχάλινον κεκτημένον τὸ στόμα, βίᾳ ὑπὸ τοῦ λόγου

who are said to have reverted to their original state, dragging out a painful existence with never any rest from woe. What, again, is our object in saying all this? Evidently, I must, every time, rein in my discourse, like a horse, and not let it run away with me as though it had no bridle