s through its form. Now faith works
through charity. Therefore the love of charity is the form of faith.

_I answer that,_ As appears from what has been said above (I-II, Q.
1, A. 3; I-II, Q. 18, A. 6), voluntary acts take their species from
their end which is the will's object. Now that which gives a thing
its species, is after the manner of a form in natural things.
Wherefore the form of any voluntary act is, in a manner, the end to
which that act is directed, both because it takes its species
therefrom, and because the mode of an action should correspond
proportionately to the end. Now it is evident from what has been said
(A. 1), that the act of faith is directed to the object of the will,
i.e. the good, as to its end: and this good which is the end of
faith, viz. the Divine Good, is the proper object of charity.
Therefore charity is called the form of faith in so far as the act
of faith is perfected and formed by charity.

Reply Obj. 1: Charity is called the form of faith because it quickens
the act of faith. Now nothing hinders one act from being quickened by
different habits, so as to be reduced to various species in a certain
order, as stated above (I-II, Q. 18, AA. 6, 7; I-II, Q. 61, A. 2)
when we were treating of human acts in general.

Reply Obj. 2: This objection is true of an intrinsic form. But it is
not thus that charity is the form of faith, but in the sense that it
quickens the act of faith, as explained above.

Reply Obj. 3: Even obedience, and hope likewise, and whatever other
virtue might precede the act of faith, is quickened by charity, as
we shall show further on (Q. 23, A. 8), and consequently charity is
spoken of as the form of faith.
_______________________

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

Whether Lifeless Faith Can Become Living, or Living Faith, Lifeless?

Objection 1: It would seem that lifeless faith does not become
living, or living faith lifeless. For, according to 1 Cor. 13:10,
"when that which is perfect is come, that which is in part shall be
done away." Now lifeless faith is imperfect in comparison with living
faith. Therefore when living faith comes, lifeless faith is done
away, so that they are not one identical habit.

Obj. 2: Further, a dead thing does not become a living thing. Now
lifeless faith is dead, according to James 2:20: "Faith without works
is dead." Therefore lifeless faith cannot become living.

Obj. 3: Further, God's grace, by its advent, has no less