Original sin is the name given to the first sin committed by the first human beings, Adam and Eve. Genesis 3 tells how God placed Adam and Eve in the Garden of Paradise, telling them that they could eat of any tree in the garden except the one in the middle, the Tree of Knowledge of Good and Evil. Later, the serpent tempts them to eat fruit from this tree.
Sacred art has traditionally portrayed Eve handing her husband Adam an apple, but the Bible does not identify the kind of fruit or tree. At some point in the past, someone depicted the Fall of Adam and Eve in art, using an apple to represent the fruit, and everyone has followed suit since.
The key here is not what kind of fruit, but that it was the sin of disobedience. Notice how God gave them all kinds of alternatives. There were many other trees in the Garden, but only one was forbidden. The one forbidden fruit was more appealing than all the rest. That is the insanity of sin: it often makes no sense.
Once our first parents sinned, human nature itself was wounded. That is because sin is not just a violation of divine law, but is also a spiritual disease, an infection, a bacterium, and an injury to the soul. Punishment was swift after God discovered that man and woman had sinned. “To the woman he said: ‘I will intensify the pangs of your childbearing; in pain shall you bring forth children. Yet your urge shall be for your husband, and he shall be your master.’ To the man he said: ‘Because you listened to your wife and ate from the tree of which I had forbidden you to eat, Cursed be the ground because of you! In toil shall you eat its yield all the days of your life'” (Genesis 3:16–17).
Not only were they exiled from the Garden of Eden, but the aftereffects of sin now infected human nature. Original sin had the consequences of:
1. Loss of the gift of immortality: death became part of human nature.
2. Loss of the gift of impassibility: pain and suffering became part of human nature.
3. Loss of sanctifying grace: heaven would be closed to man until he was redeemed by the Messiah.
Original sin not only hurt our relationship with God, but it deeply wounded human nature the same way a horrible virus or bacteria harms our bodies. Some diseases or their effects can be inherited by subsequent generations. Every human being since Adam and Eve inherited a wounded human nature. What was that wound? Martin Luther (1483–1546) thought original sin destroyed human nature, or at least made it so putrid and repugnant that God had to cover us with grace to hide our ugliness. The Council of Trent (1545–1563) repudiated that idea and taught that human nature was not decrepit or corrupt, merely wounded. What is wounded can be healed.
Trent also taught that the effects of original sin were threefold:
1. Darkening of the intellect: sometimes we cannot reason clearly when tempted.
2. Weakening of the will: sometimes we know what we should do, but lack the courage or strength to resist temptation.
3. Disordering of the lower passions: often our emotions overpower our reason.
The only remedy for original sin and its effects is divine grace, a supernatural gift from God to help our souls. The grace of baptism is sanctifying grace. It washes away original sin and restores the broken relationship between the created (man) and the Creator (God). Baptismal grace also makes one a child of God by adoption. It enables us to receive more divine grace from the other sacraments.
Divine grace also treats the wounded human nature by enlightening the intellect, strengthening the will and reordering the lower passions. Concupiscence is the theological word used to describe our natural inclination or proclivity to sin, which is another effect of original sin.