The Catholic Church divides sin into different categories to distinguish its severity, as well as how one falls into (or inherits) it. The first major distinction in sin is between Original and Actual Sin. Every person inherits Original Sin by virtue of being conceived. Actual Sin refers to sin which people incur by committing it.
Our first parents, Adam and Eve, sinned in the Garden of Eden by disobeying God. Consequently, they and their descendants received “Original Sin.” All souls have Original Sin from the moment of their conception, through no fault of their own. There are two effects of Original Sin, one eternal and the other temporal. The eternal consequence of Original Sin is Hell. The temporal consequence is concupiscence, or a tendency to commit sin.
The Church did not invent Original Sin. Some will object to this foundational teaching by asserting that St. Augustine made up the doctrine. These and other statements misunderstand the Church’s reasons for teaching such a doctrine. Not only does the doctrine have much scriptural basis, but is apparently evident in the world. We could spend pages listing all the crimes humanity has ever committed, and go into depth in all the evil thoughts mankind has ever harbored. We fail time and time again. Why do ideologies such as communism inevitably fail, even though they seek to revert man to his original manner of living in neolithic times? In fact, these ideologies fail because they seek to revert man to this state. They seek, knowingly or not, to discard Jesus Christ’s sacrifice in favor of the yoke of sin. Christ died to free man from Hell – the eternal effect of Original Sin. It is only by Christ’s grace, living as new men in the “last Adam,” Jesus Christ, that we can become the great saints God wants us to be (1 Cor 15:45).
Original Sin is something everyone is born with (except Christ and the Blessed Virgin Mary), and is inherited from Adam and Eve because everyone can trace their origin back to Adam and Eve. However, it is not inherited via seminal production. Rather, since mankind is in a sense “one man,” with “one common nature” (that of Adam), we inherit the sin of Adam (S.T. II, PI, Q. 81, Art. 1). If we were completely separate from our forefather, Adam, then we would not inherit his sin, for the son of a murderer is not a murderer, and it would be absurd to ascribe the guilt of murder to him. Likewise, as we do not ascribe the guilt of murder to the hand that shot the pistol, but to the whole person, so we do not only ascribe the guilt of the Fall to Adam alone, but to all who are born with his nature (in his line) (S.T. II, PI, Q. 81, Art. 1). We here reference Adam, not Eve, because if only Eve had fallen, and not Adam, then we would not inherit Original Sin, because “the active principle of generation is from the father” (S.T. II, PI, Q. 81, Art. 5). Evident in the reproductive act, the man is the giver of the seed, whereas the woman is the receiver of the seed. So with Original Sin, the father, Adam, gave Original Sin to his descendants, and thus to all mankind.
The Sacrament of Baptism washes away the eternal effect of Original Sin, while it gives us graces to resist concupiscence. This teaching does not mean that God cannot choose to forgive, for example, a miscarried child, who dies before he or she can be baptized. But it does mean that for us who live on this earth, we must be baptized to know for sure that the eternal effects of Original Sin are washed away from our souls. Even after baptism, we still have the temporal effect of Original Sin (an inclination to commit sin, concupiscence). Before the Fall, because Adam and Eve had no Original Sin, they had no inclination to sin – hence why after the Fall, they notice each other’s nakedness and become ashamed. Our inclination to commit sin means that we are continually tempted, but we can unite all the struggles we experience to Christ’s sacrifice on the Cross, in order to overcome sin and share in the redemption of mankind.
As we discussed above, Original Sin explains why humans have a tendency to commit sin, despite being made in the image and likeness of God. However, Scripture also gives evidence for Original Sin.
Genesis 3 addresses the Fall and shows how God punishes Adam and Eve for disobeying Him. They are in disgrace before God and He sentences them to toil and suffer pain, implying that they did not have to do these things in their preternatural (pre-Fall) state. They are also cut off from the Garden of Eden, and are thus banished from access to the “tree of life” (Gen 3:24).
In Psalm 51, the psalmist proclaims that he “was brought forth in iniquity, and in sin did [his] mother conceive him” (Ps 51:5). Throughout this psalm, David repents to the Lord, begging Him for forgiveness, after the king had committed adultery with Bathsheba, and indirectly murdered her husband. However, despite recounting his personal sins, he also makes the point that he had a stain of sin from his birth – some sort of Original Sin.
St. Paul details how “sin came into the world through one man, and death through sin,” and that “death reigned from Adam to Moses, even over those whose sins were not like the transgression of Adam” (Rom 5:12, 14). Death, both spiritual and temporal, come through Original Sin, even to those who did not transgress as Adam did. Moreover, “Adam…was a type of” Christ (Rom 5:14). Therefore, since “by a man came death, by a man has come also the resurrection of the dead” (1 Cor 15:21). We who die are liberated from our eternal death to eternal life by Christ. There was a dimension to Christ’s Passion beyond the forgiveness of personal sins – it cleansed us of Original Sin as well.
The Church did not make up Original Sin. Church fathers uphold this truth, but did not create it out of thin air. As with everything God revealed to His Church by the Deposit of Faith, the truth of Original Sin is evident from Scripture and Tradition.