act, whose
principle needs to be in itself, as stated above (I-II, Q. 6, A. 1):
so that it would follow that to love is not a voluntary act, which
involves a contradiction, since love, of its very nature, implies an
act of the will.

Likewise, neither can it be said that the Holy Ghost moves the will
in such a way to the act of loving, as though the will were an
instrument, for an instrument, though it be a principle of action,
nevertheless has not the power to act or not to act, for then again
the act would cease to be voluntary and meritorious, whereas it has
been stated above (I-II, Q. 114, A. 4) that the love of charity is
the root of merit: and, given that the will is moved by the Holy
Ghost to the act of love, it is necessary that the will also should
be the efficient cause of that act.

Now no act is perfectly produced by an active power, unless it be
connatural to that power by reason of some form which is the
principle of that action. Wherefore God, Who moves all things to
their due ends, bestowed on each thing the form whereby it is
inclined to the end appointed to it by Him; and in this way He
"ordereth all things sweetly" (Wis. 8:1). But it is evident that the
act of charity surpasses the nature of the power of the will, so
that, therefore, unless some form be superadded to the natural power,
inclining it to the act of love, this same act would be less perfect
than the natural acts and the acts of the other powers; nor would it
be easy and pleasurable to perform. And this is evidently untrue,
since no virtue has such a strong inclination to its act as charity
has, nor does any virtue perform its act with so great pleasure.
Therefore it is most necessary that, for us to perform the act of
charity, there should be in us some habitual form superadded to the
natural power, inclining that power to the act of charity, and
causing it to act with ease and pleasure.

Reply Obj. 1: The Divine Essence Itself is charity, even as It is
wisdom and goodness. Wherefore just as we are said to be good with
the goodness which is God, and wise with the wisdom which is God
(since the goodness whereby we are formally good is a participation
of Divine goodness, and the wisdom whereby we are formally wise, is a
share of Divine wisdom), so too, the charity whereby formally we love
our neighbor is a participation of Divine charity. For this manner of
speaking is common among the Platonists, with whose doctrines
Augustine was imb