Now virtue has no matter “out of which” it is formed, as neither has any other accident; but it has matter “about which” it is concerned, and matter “in which” it exists, namely, the subject.  The matter about which virtue is concerned is its object, and this could not be included in the above definition, because the object fixes the virtue to a certain species, and here we are giving the definition of virtue in general.  And so for material cause we have the subject, which is mentioned when we say that virtue is a good quality “of the mind.”

The end of virtue, since it is an operative habit, is operation.  But it must be observed that some operative habits are always referred to evil, as vicious habits:  others are sometimes referred to good, sometimes to evil; for instance, opinion is referred both to the true and to the untrue:  whereas virtue is a habit which is always referred to good:  and so the distinction of virtue from those habits which are always referred to evil, is expressed in the words “by which we live righteously”:  and its distinction from those habits which are sometimes directed unto good, sometimes unto evil, in the words, “of which no one makes bad use.”

Lastly, God is the efficient cause of infused virtue, to which this definition applies; and this is expressed in the words “which God works in us without us.”  If we omit this phrase, the remainder of the definition will apply to all virtues in general, whether acquired or infused.

Reply Obj. 1:  That which is first seized by the intellect is being:  wherefore everything that we apprehend we consider as being, and consequently as one, and as good, which are convertible with being.  Wherefore we say that essence is being and is one and is good; and that oneness is being and one and good:  and in like manner goodness.  But this is not the case with specific forms, as whiteness and health; for everything that we apprehend, is not apprehended with the notion of white and healthy.  We must, however, observe that, as accidents and non-subsistent forms are called beings, not as if they themselves had being, but because things are by them; so also are they called good or one, not by some distinct goodness or oneness, but because by them something is good or one.  So also is virtue called good, because by it something is good.

Reply Obj. 2:  Good, which is put in the definition of virtue, is not good in general which is convertible with being, and which extends further than quality, but the good as fixed by reason, with regard to which Dionysius says (Div.  Nom. iv) “that the good of the soul is to be in accord with reason.”

Reply Obj. 3:  Virtue cannot be in the irrational part of the soul, except in so far as this participates in the reason (Ethic. i, 13).  And therefore reason, or the mind, is the proper subject of virtue.

Reply Obj. 4:  Justice has a righteousness of its own by which it puts those outward things right which come into human use, and are the proper matter of justice, as we shall show further on (Q. 60, A. 2; II-II, Q. 58, A. 8).  But the righteousness which denotes order to a due end and to the Divine law, which is the rule of the human will, as stated above (Q. 19, A. 4), is common to all virtues.