Plato, Laws 666c

σκληροτέρου τὸ τῆς ψυχῆς ἦθος, καθάπερ εἰς πῦρ σίδηρον ἐντεθέντα γιγνόμενον, καὶ οὕτως εὐπλαστότερον εἶναι; πρῶτον μὲν δὴ διατεθεὶς οὕτως ἕκαστος ἆρʼ οὐκ ἂν ἐθέλοι προθυμότερόν γε, ἧττον αἰσχυνόμενος, οὐκ ἐν πολλοῖς ἀλλὰ ἐν μετρίοις, καὶ οὐκ ἐν ἀλλοτρίοις ἀλλʼ ἐν οἰκείοις, ᾄδειν τε καὶ ὃ πολλάκις εἰρήκαμεν ἐπᾴδειν; καὶ πολύ γε. εἰς μέν γε τὸ προάγειν τοίνυν αὐτοὺς μετέχειν ἡμῖν ᾠδῆς οὗτος ὁ τρόπος οὐκ ἂν παντάπασιν ἀσχήμων

may lose its hardness and become softer and more ductile, even as iron when it has been forged in the fire. Will not this softer disposition, in the first place, render each one of them more ready and less ashamed to sing chants and incantations (as we have often called them), in the presence, not of a large company of strangers, but of a small number of intimate friends? Yes! much more ready. So then, for the purpose of inducing them