Hesiod Works and Days, 289-90

 

“The gods made sweat the price for virtue.”

 

 

τῆς δ’ ἀρετῆς ἱδρῶτα θεοὶ προπάροιθεν ἔθηκαν

ἀθάνατοι·

Menander, Monostichoi 433

“Man’s greatest weapon is virtue”

 

ὅπλον μέγιστόν ἐστιν ἡ ἀρετή βροτοῖς

 

This sounds more like something Aristotle might say.

 

This is the result of a google image search for 'greek virtue'