I have summarized all four articles of question 110 in the prima secunda of Thomas Aquinas’s Summa Theologica: “Of the Grace of God As Regards Its Essence.”   All quotations from the Summa are taken from the English Translation, Summa Theologica, trans. the Fathers of the English Dominican Province, 5 vols., rev. ed. 1948; repr., Notre Dame, Indiana: Ave Maria Press, 1981.

110.1 Grace Implies Something in the Soul

IN SUM: Grace is not limited to the forgiveness of sins, but signifies various gifts bestowed on man by God including God’s causing good in the soul of the creature.  Thus, grace implies something in the soul, which is God’s love effecting new goodness in the soul of the creature.

Grace can mean three things.

1. anyone’s love (e.g. the “good graces” of someone)
2. any gift freely bestowed (i.e. given gratis) (e.g. someone’s “act of grace”)
3. a grateful recompense of a gift given gratis (someone’s gratitude)

Any gift freely given depends on the love, and likewise any gratitude for a gift freely given depends on the gift freely given.  Therefore, each subsequent definition after the first depends on the previous notion (#2 presupposes #1, #3 presupposes #2).

With regard to #1, a distinction must be made.  Whereas a creature’s love presupposes a perceived good without wholly causing that good, God’s love is always the cause of any creaturely good.  “Therefore it is clear that every love of God is followed at some time by a good caused in the creature but not co-eternal with the eternal love” (I-II.110.1).

Now God’s common love causes the good of any creature’s existence and “natural being,” but God’s special love “draws the rational creature above the condition of its nature to a participation of the Divine good” and “it is by this love that God simply wishes the eternal good, which is Himself, for the creature” (I-II.110.1).

Thus, on the one hand, the grace of God implies a gift freely given to a rational creature and his special love even signifies something bestowed on the soul of a created person.  On the other hand, the “something” in the soul is simply God’s eternal love.

The word “grace” has been especially applied to the forgiveness of sins, but as Augustine said, we must not limit the word “grace” merely to forgiveness of sins.  Yet even “the remission of sins does not take place without some effect divinely caused in us, as will appear later (Q. 113, A. 2)” (I-II.110.1.ad.3).

110.2 Grace Refers to Qualities of the Soul

IN SUM: God not only moves natural creatures to natural good but also bestows upon them certain forms and powers that are principles of acts in order that they be inclined to these movements in an easy and natural way, so also God not only moves the soul in grace, but freely bestows upon the soul new qualities in order that it might be moved easily and sweetly to the supernatural good.

Whoever has God’s grace should be understood to have also some effect of this grace within them, as stated previously.  People are helped by God’s gratuitous will in two ways.  First, God moves the soul of a person to know, will, and do something, and in these ways the grace of God is not considered a quality per se, but a movement of the soul.  “Motion is the act of the mover in the moved” (I-II.110.2).  Second, God infuses a habitual gift into the soul so that they are enabled to acquire the supernatural good with ease [and pleasure?].  In this second way, grace can be considered a quality or as consisting in qualities.

Grace acts upon the soul after the manner of a formal cause, “as whiteness makes a thing white, and justice, just” (I-II.110.2.ad.1).

Grace is not considered a “substance” of the soul because it is not part of the soul’s nature but the soul obtains it through a participation in the Divine goodness.  Thus, what is substantial in God becomes accidental in the soul by participation.  Grace can be considered as simply a participation in this divine goodness.  This participation, however, is imperfect.  While grace is nobler than the substance of the soul, the soul “has its being” more perfectly in its own substance than in grace, since grace is accidental to the soul by participation. (I-II.110.2.ad.2).

“The being of an accident is to inhere,” thus accidents are said to have being inasmuch as “by them something is.”  Thus accidents belong to beings, but are not called “beings” proper.  Properly speaking, then, no accident comes into being or is corrupted.  However, the subject of an accident can begin or cease to be in act while having this accident. “And thus grace is said to be created inasmuch as men are created [anew] with reference to it, i.e., are given a new being out of nothing, i.e. not from merits, according to Eph. Ii. 10, created in Jesus Christ in good works.” (I-II.110.2.ad.3).

110.3 Grace is Not the Same as Virtue

IN SUM: Because grace precedes charity and the virtues, it is not itself a virtue.  However, the infused virtues are oriented to grace (i.e. participation in the Divine nature) as acquired virtues are oriented to human nature.  Faith is the first manifestation of grace, but grace cannot be reduced to faith or any of the virtues because it is the root of all infused virtues.  Grace is a certain disposition presupposed by the infused virtues [i.e. the disposition of God himself?].

Grace is neither faith nor hope, and as Augustine says “grace foreruns charity.”  Therefore it is not a virtue. (I-II.110.3)

Aristotle defined virtue as “a disposition of what is perfect—and I call perfect what is disposed according to its nature” (I-II.110.3).  But infused virtues are disposed according to a higher end than human nature—namely, our participation in the nature of God (cf. 2 Pet. 1:4).  “And it is in respect of receiving this nature that we are said to be born again sons of God” (I-II.110.3).

Just as “the acquired virtues enable a man to walk, in accordance with the natural light of reason, so do the infused virtues enable a man to walk as befits the light of grace” (I-II.110.3).

“Augustine calls faith that worketh by charity grace, since the act of faith of him that worketh by charity is the first act by which sanctifying grace is manifested.” (I-II.110.3.ad.1).

Grace is “the root of goodness in man” (I-II.110.3.ad2).

Grace can be reduced to a habit or disposition, yet is not the same as virtue because grace “is a certain disposition which is presupposed to the infused virtues, as their principle and root” (I-II.110.3.ad.3).

110.4 Grace Presides Principally In the Essence of the Soul

IN SUM: Since grace is prior to virtue, it must be in the essence of the soul rather than in the powers of the soul.  Grace is the principle of meritorious works through the virtues.

“By grace we are born again sons of God.  But generation terminates at the essence prior to the [exercise of?] powers.  Therefore grace is in the soul’s essence prior to being in the powers.” (I-II.110.4)

If grace were virtue, grace would necessarily reside in the powers of the soul.  But since, as we have seen, grace is prior to virtue, it must have a subject prior to the powers of the soul.  Therefore, it must be in the essence of the soul.  Just as a person’s will participates in the Divine love through the virtue of charity, so does the nature of her soul participate in the Divine Nature (and become more like that Divine Nature) through regeneration or re-creation.

The powers of the soul flow from the essence of the soul.  It is through the powers of the soul that the essence of the soul is the principle of vital deeds.  Likewise, it is through the medium of the virtues that grace is the principle of meritorious works. (I-II.110.4.ad.1)