Many people, whether Christian or not, have heard of the basic Christian teaching of
“original sin.” Most people, even Christians, are not really sure what it means.
Sometimes we speak of it as though we have a curse that can’t be shaken off.
Sometimes we use the expression to describe unexplainable behavior, such as
selfishness, in ourselves and others. Generally we think of it as a “thing.”
When Thomas Aquinas comments on today’s second reading (Romans 5:12-15), he
summarizes the traditional teaching on original sin. According to Thomas, God designed
the human person with a mind that would be ordered to God. The body and the senses
would be subject to the mind, which is “reason.”
The traditional name for this condition of our first parents is “original justice.” In this
situation, spiritual and physical elements of humans would be orderly not only in relation
to individuals but also in relation to with others and humans would have a certain peace
with external things of nature that would serve them and not harm them (Commentary
on Romans, 416).
When Adam turned from God, he became disoriented. His mind no longer controlled his
body or his senses and his sin affected the way that he perceived others. Genesis tells
us that the man and women hid because they have become afraid of God. Adam and
Eve became aware of their nakedness, indicating that they have lost their innocence.
One of their sons (Cain) killed his brother (Abel) out of jealousy. Adam no longer felt
connected with natural things
As we can see, for Thomas and the Church, original sin is not a sin in the sense of
something we have actually chosen to do: “Actual sin is a person’s sin because it is
committed through the will of the person sinning” (Commentary on Romans, 409).
Original sin “is the sin of the nature committed through the will of the source of human
nature” (Commentary on Romans, 409). Or, as Thomas observes, “a person [is]
infected [in] the nature” that we inherit.
Yet, original sin is not a thing. Thomas describes it as a “defect”: “This defect is a lack of
original justice” (Commentary on Romans, 410). Thus, rather than being connected with
God, connected within ourselves and with others, we are disconnected and have a
distorted view of God, others and external things.
In his encyclical Laudato Si, Pope Francis describes this situation in a contemporary
application. He speaks of the “profound teachings” present in “the symbolic and
narrative” language of Genesis.
According to the Pope, human life is grounded in “three fundamental and closely
intertwined relationships: with God, with our neighbor and with the earth itself.”
Sin is a “rupture” that breaks this harmony, as we presume to take God’s place and
refuse to accept “our creaturely limitations.”

Pope Francis acknowledges that this rupture affects our original “harmonious
relationship with nature,” which instead has become “conflictual.” Pope Francis
laments: today sin is manifest in all its destructive power in wars, the various forms of
violence and abuse, the abandonment of the most vulnerable, and attacks on nature
(Pope Francis, Laudato Si, 66).
Paul’s purpose in the second reading today, Romans 5:12-15, is not to depress us as
though we are stuck in a hopeless situation. His intention to point us to the solution.
Paul says that Adam, the original source of human nature was a “figure of the one to
come” (Rom 5:14). Christ reorients humanity: “For if by the offense of one, many died:
much more the grace of God and the gift, by the grace of one man, Jesus Christ, has
abounded to many” (Rom 5:15).
Thomas reflects: “Just as sin and death entered the world through Adam, so justice and
life entered through Christ” (Commentary on Romans, 429).
For Thomas, sin arises from weakness but grace from God’s goodness: “Sin came from
the weakness of the human will, but grace comes from the immensity of divine
goodness, which excels the human will, especially in its weakness. Therefore the power
of grace exceeds every sin. The gift of grace exceeds the offense of Adam”
(Commentary on Romans, 431).
Thomas notes: “God’s grace, which is stronger, extends much more abundantly”
(Commentary on Romans, 432).
Christ’s power not only overcomes original sin but all our personal sins , our “actual
sins,” as Thomas explains: “God’s grace reached man not only to erase sin incurred
from Adam but also to remove actual sins and to bestow many other blessings, ‘God is
able to provide you with every blessing in abundance’” (2 Cor 9:8)” (Commentary on
Romans, 433).
God’s grace comes to us through Jesus, as Thomas affirms: “Grace is poured out by
God upon many, in order that we might receive it through Christ, in whom every fullness
of grace is found: ‘From His fullness we have all received, grace upon grace’ (Jn 1:16).”
Christ breaks the power of original sin in us through the sacrament of Baptism. Thomas
acknowledges that we still struggle with the impulses of our bodies: “Through baptism a
man is freed from original sin as far as the mind is concerned, but the infection of sin
remains as far as the flesh is concerned” (Commentary on Romans, 420). Thomas
recalls Paul’s words: “I serve the law of God with the mind but with the flesh, the law of
sin” (Rom 7:25).
The Council of Trent uses the word “concupiscence” to affirm that “an inclination” to sin
is not sin itself:

… there remains in the baptized concupiscence of an inclination, although this is
left to be wrestled with, it cannot harm those who do not consent, but manfully
resist by the grace of God…This concupiscence … the Catholic Church has
never understood to be called sin… (Denzinger, The Sources of Catholic Dogma,
791).
We can be assured that if we persevere the war is won. At a certain point during the
Second World War, victory was certain for the allies even though the war continued.
Many of us think our own sins have a greater effect upon us than does the grace of
Christ, yet Thomas insists: “Not only does Christ’s grace more abound for many than
Adam’s sin but it produces a greater effect. For the effect of a stronger cause is
stronger. Hence… since grace is stronger than Adam’s sin, it follows that it produces a
greater effect” (Commentary on Romans, 436).
Denis Vincent Wiseman, O.P.
References to St. Thomas Aquinas’ Commentary on Romans are taken from the
translation begun by Fr. Fabian R. Larcher, O.P. and edited by J. Mortensen and E.
Alarcón. The translation was published by the Aquinas Institute for the Study of Sacred
Doctrine, Lander, Wyoming, in 2012, pp. 137-149.