οὐ γὰρ πράξιν ἀγαθὴν, ἀλλὰ καὶ εὖ ποεῖν αὐτὴν → it does not suffice to do good–one must do it well
A = εὔτονον or ἰσχυρόν, Hsch., EM234.24, Eust.1560.32.