Plato, Laws 729c

λέγοντά τι τῶν αἰσχρῶν, ὡς ὅπου ἀναισχυντοῦσι γέροντες, ἀνάγκη καὶ νέους ἐνταῦθα εἶναι ἀναιδεστάτους· παιδεία γὰρ νέων διαφέρουσά ἐστιν ἅμα καὶ αὐτῶν οὐ τὸ νουθετεῖν, ἀλλʼ ἅπερ ἂν ἄλλον νουθετῶν εἴποι τις, φαίνεσθαι ταῦτα αὐτὸν δρῶντα διὰ βίου. συγγένειαν δὲ καὶ ὁμογνίων θεῶν κοινωνίαν πᾶσαν ταὐτοῦ φύσιν αἵματος ἔχουσαν τιμῶν τις καὶ σεβόμενος, εὔνους ἂν γενεθλίους θεοὺς εἰς παίδων αὑτοῦ σπορὰν ἴσχοι κατὰ λόγον. καὶ μὴν τό γε φίλων καὶ ἑταίρων

for where the old are shameless, there inevitably will also the young be very impudent. The most effective way of training the young—as well as the older people themselves—is not by admonition, but by plainly practising throughout one’s own life the admonitions which one gives to others. By paying honor and reverence to his kinsfolk, and all who share in the worship of the tribal gods and are sprung from the same blood, a man will, in proportion to his piety, secure the goodwill of the gods of Birth to bless his own begetting of children. Moreover,