Plato, Laws 660a

πώμασι τὴν χρηστὴν πειρῶνται τροφὴν προσφέρειν οἷς μέλει τούτων, τὴν δὲ τῶν πονηρῶν ἐν ἀηδέσιν, ἵνα τὴν μὲν ἀσπάζωνται, τὴν δὲ μισεῖν ὀρθῶς ἐθίζωνται. ταὐτὸν δὴ καὶ τὸν ποιητικὸν ὁ ὀρθὸς νομοθέτης ἐν τοῖς καλοῖς ῥήμασι καὶ ἐπαινετοῖς πείσει τε, καὶ ἀναγκάσει μὴ πείθων, τὰ τῶν σωφρόνων τε καὶ ἀνδρείων καὶ πάντως ἀγαθῶν ἀνδρῶν ἔν τε ῥυθμοῖς σχήματα καὶ ἐν ἁρμονίαισιν μέλη ποιοῦντα ὀρθῶς ποιεῖν.

and drinks that are pleasant, but unwholesome nutriment in the opposite, so that they may form the right habit of approving the one kind and detesting the other. Similarly in dealing with the poet, the good legislator will use noble and laudable phrases to persuade him—and, failing persuasion, he will compel him—to portray by his rhythms the gestures, and by his harmonies the tunes, of men who are temperate, courageous, and good in all respects, and thereby to compose poems aright.