Philipp Melanchthon, in his Philosophiae moralis epitome (Summary of Moral Philosophy), has this to say about his (Aristotelian) view of virtue, and the relation of knowledge, will, and reason in the doing of virtue:
Est autem simplicissima et planissima definitio in philosophia: Virtus est habitus, qui inclinat voluntatem ad obediendum rectae rationi. Duae sunt enim principales et immediatae causae virtutis, notitia gubernatrix et voluntas obtemperans…, quia divinitus insitae sunt menti quaedam notitiae, discernentes honesta et turpia, et est ordinatio Dei, ut his notitiis rectis obtemperet voluntas.
“It is, moreover, the simplest and plainest definition in philosophy: virtue is a habit, which inclines the will toward obeying right reason. For there are two principal and immediate causes of virtue, the notion that governs and the will that obeys…, 1 because certain 2 notions, discerning the honorable and the shameful, have been implanted by God in the mind, and it is the ordinance of God that the will obey these right notions.”