Plato, Laws 718e

γίγνεσθαι, τὸν δὲ Ἡσίοδον οἱ πολλοὶ σοφὸν ἀποφαίνουσι λέγοντα ὡς ἡ μὲν ἐπὶ τὴν κακότητα ὁδὸς λεία καὶ ἀνιδιτὶ παρέχει πορεύεσθαι, μάλα βραχεῖα οὖσα, τῆς δὲ ἀρετῆς, φησίν, ἱδρῶτα θεοὶ προπάροιθεν ἔθηκαν ἀθάνατοι, μακρὸς δὲ καὶ ὄρθιος οἶμος ἐς αὐτήν,

the majority, indeed, serve to show how wise Hesiod was when he said, smooth is the way that leadeth unto wickedness, and that no sweat is needed to traverse it, since it is passing short, but (he says)—In front of goodness the immortal gods Have set the sweat of toil, and thereunto Long is the road and steep, and rough withal