Why did the Son of God take our human nature? Thomas points out that everything acts
according to what it is, just as humans act in a reasonable way. How would we describe God’s
nature? Thomas thinks the description of God by the six-century Syrian monk/theologian,
Dionysius 1 quickly gets to the heart of what God’s nature is. Thomas explains: “The very nature
of God is goodness, as is clear from Dionysius. Hence what belongs to the essence of goodness
befits God” (3a. 1, 1). 2
According to Thomas, everything acts as it is. If God’s nature is goodness, then God acts
in good ways. Thomas draws upon another principle of Dionysius, “It belongs to the essence of
goodness to communicate itself to others…” (3a. 1, 1). We know that good people are generous
but God’s goodness and generosity exceed whatever we experience in our human encounters.
Thomas explains: “It belongs to the essence of the highest good to communicate itself in the
highest manner to the creature” (3a. 1, 1). God’s generosity flows from His goodness. God’s
generosity and His goodness are the ultimate explanation for the Incarnation.
Why was the Incarnation good? From the perspective of the divinity of the Son of God,
which surpasses our humanity, there doesn’t seem to be any reason why it would be appropriate
or fitting for the Son of God to take our nature to Himself. The one way that it seems
appropriate is for our sakes, as Thomas explains that “God by reason of His infinite goodness
should unite human nature to Himself for our salvation” (3a. 1, 1, ad 2). 3
Was the Incarnation the only way we could have been saved? Thomas recalls John’s
Gospel: “God so loved the world that He gave His only-begotten Son so that those who believe
in Him may not perish but may have eternal life” (Jn 3:16). Thomas thinks that the Incarnation
was not the only way that we could be saved but it is a way that achieves its goal “better and
more conveniently” (3a. 1, 2). Thomas offers the example of a horse as a better, although not
necessary, way to travel. We might think of a car or a plane as a better way.
Why is the Incarnation a better way to bring about our salvation? According to Thomas
the Incarnation is most effective in achieving God’s purpose “for the restoration of human
nature.” The Incarnation strengthens our faith because we are more likely to believe God than to
believe each other. When Jesus speaks to us, “God Himself speaks.”
The Incarnation strengthens our hope. Thomas recalls Augustine’s words: “Nothing was
so necessary for raising our hope as to show us how deeply God loved us. And what could afford

1 Dionysius is the author of De Divinis Nominibus, part of four theological and liturgical works. He wrote
about the year 500. Because he wrote under the name of Dionysius who was converted by Paul at the Aereopagus in
Athens, he is often called Pseudo-Dionysius or Dionysius the Aereopagite. Thomas finds his answers to God’s
nature in the first part of the De Divinis Nominibus.
2 References are to the Summa Theologica, trans. English Dominicans (New York: Benziger Brothers, Inc,
1947), pp. 2025-2027. The citations give the part of the Summa, the question and the article. In this case, it is the
third part, the first question and the first article in that question.
3 The preposition “ad” indicates that this is Thomas’ reply to one of the objections that he used to introduce
the question.

us a stronger proof of this than that the Son of God should become a partner with us of human
nature?” 4
Our love for God, “is most greatly enkindled by the Incarnation” because we see how
much God loves us. Thomas refers to Augustine’s words “What greater cause is there of the
Lord’s coming than to show God’s love for us? … If we have been slow to love, at least let us
hasten to love in return.” 5
The Incarnate Son of God teaches us the right way to live by His example. Thomas
alludes to Augustine’s words: “Humans who are seen are not to be followed but God who cannot
be followed is not seen. God was made man that He might be seen by us and that we might see
the one we should follow.” 6
Thomas states that “full participation of the Divinity is our true happiness and the goal of
human life.” This sharing in divinity “is bestowed upon us by Christ’s humanity.” Thomas
remembers Augustine’s affirmation, “God was made man that man might be made God.” 7
Thomas adds that the Incarnation delivers us from evil. This liberation begins by
instructing us not to be overwhelmed by the devil. He recalls Augustine’s words that since
“human nature is joined to God as to become one with Him in person,” there is no cause to be
affected by evil spirits since “they are without flesh” and the Son of God has come closer to us
by taking our flesh. 8
We are also taught “how great is the dignity of human nature,” which should make us
reluctant to sin. Thomas evokes Augustine: “God showed us the exalted place that human nature
holds in creation by appearing to men as a true man.” 9 In a similar way, St. Leo instructs us: “O
Christian, acknowledge your dignity; having been made a sharer in the divine nature, refuse to
fall back into your previous worthlessness by your conduct.” 10
Again, Thomas says that one of the effects of the Incarnation is “to do away with human
presumption. He refers to Augustine, “The grace of God, with no preceding merits on our part, is
shown to us in the man Christ.” 11 Thomas affirms that Jesus’ humility can heal our pride, as
Augustine says, “Man’s pride, which is the greatest stumbling-block to our clinging to God, can
be convinced and cured by humility so great.” 12
The Incarnation rescues us from slavery. He returns to Augustine, this “should be done in
such a way that the devil is overcome by the justice of a man, Jesus Christ.” 13 Thomas adds that
4 Augustine, De Trinitate (“On the Trinity”), XIII, 10.
5 Augustine, Liber de catechizandis rudibus (“The Instruction of the Unlearned,” 4.
6 Augustine, Sermo CCCLXXI, 2: PL 39, 1660.
7 Augustine, Sermo CXXVIII PL 39, 1997.
8 Augustine, De Trinitate XIII, 17, PL 42, 1031.
9 Augustine, De Vera Religione 16. PL 34, 134-5.
10 Leo, Sermo CCI. PL 54, 192.
11 Augustine, De Trinitate, XIII, 17.
12 Augustine, De Trinitate, XIII, 17.
13 Augustine, De Trinitate, XIII, 14. An earlier source along this line is Irenaeus, Adversus haereses IV, 28.

this is accomplished by “Christ making satisfaction for us.” Since a human person could not
make satisfaction for the whole human race, Thomas explains, “It is fitting, then, for Jesus Christ
to be both God and human” (3a. 1, 2). He calls upon the words of Leo: “Weakness is received by
power, humility by majesty, that one and the same mediator between God and man might die
from the one and rise from the other, and so were we fitly restored. Unless He were truly God, he
could not provide a cure; unless He were man, He could not offer an example.” 14
Thomas recognizes that ultimately the reasons for the Incarnation are God’s reasons but
theology applies reason to the mysteries revealed in faith, although always recognizing the
limitations of our human thinking when applied to divine mysteries. He notes: “There were many
other advantages resulting, which are beyond our present earth-bound comprehension.” 15

Denis Vincent Wiseman, O.P.