I answer that, Effects must needs be proportionate to their causes and principles.  Now all virtues, intellectual and moral, that are acquired by our actions, arise from certain natural principles pre-existing in us, as above stated (A. 1; Q. 51, A. 1):  instead of which natural principles, God bestows on us the theological virtues, whereby we are directed to a supernatural end, as stated (Q. 62, A. 1).  Wherefore we need to receive from God other habits corresponding, in due proportion, to the theological virtues, which habits are to the theological virtues, what the moral and intellectual virtues are to the natural principles of virtue.

Reply Obj. 1:  Some moral and intellectual virtues can indeed be caused in us by our actions:  but such are not proportionate to the theological virtues.  Therefore it was necessary for us to receive, from God immediately, others that are proportionate to these virtues.

Reply Obj. 2:  The theological virtues direct us sufficiently to our supernatural end, inchoatively:  i.e. to God Himself immediately.  But the soul needs further to be perfected by infused virtues in regard to other things, yet in relation to God.

Reply Obj. 3:  The power of those naturally instilled principles does not extend beyond the capacity of nature.  Consequently man needs in addition to be perfected by other principles in relation to his supernatural end. ________________________

FOURTH ARTICLE [I-II, Q. 63, Art. 4]

Whether Virtue by Habituation Belongs to the Same Species As Infused
Virtue?

Objection 1:  It would seem that infused virtue does not differ in species from acquired virtue.  Because acquired and infused virtues, according to what has been said (A. 3), do not differ seemingly, save in relation to the last end.  Now human habits and acts are specified, not by their last, but by their proximate end.  Therefore the infused moral or intellectual virtue does not differ from the acquired virtue.

Obj. 2:  Further, habits are known by their acts.  But the act of infused and acquired temperance is the same, viz. to moderate desires of touch.  Therefore they do not differ in species.

Obj. 3:  Further, acquired and infused virtue differ as that which is wrought by God immediately, from that which is wrought by a creature.  But the man whom God made, is of the same species as a man begotten naturally; and the eye which He gave to the man born blind, as one produced by the power of generation.  Therefore it seems that acquired and infused virtue belong to the same species.

On the contrary, Any change introduced into the difference expressed in a definition involves a difference of species.  But the definition of infused virtue contains the words, “which God works in us without us,” as stated above (Q. 55, A. 4).  Therefore acquired virtue, to which these words cannot apply, is not of the same species as infused virtue.