Definition and Origin
Original Sin refers to the doctrine that sin entered the human race through the disobedience of Adam and Eve in the Garden of Eden, as recorded in the Book of Genesis. This sin resulted in the fallen state of humanity, affecting all of Adam's descendants. Genesis 3:6 describes the pivotal moment: "When the woman saw that the tree was good for food and pleasing to the eyes, and that it was desirable for obtaining wisdom, she took the fruit and ate it. She also gave some to her husband, who was with her, and he ate it."

Theological Implications
The concept of Original Sin is foundational to understanding human nature and the need for salvation. Romans 5:12 states, "Therefore, just as sin entered the world through one man, and death through sin, so also death was passed on to all men, because all sinned." This passage highlights the transmission of sin and its consequences, emphasizing that all humans inherit a sinful nature due to Adam's transgression.

Human Nature and Depravity
Original Sin implies that human nature is inherently flawed and inclined toward sin. Psalm 51:5 reflects this condition: "Surely I was brought forth in iniquity; I was sinful when my mother conceived me." This inherent sinfulness is often referred to as "total depravity," indicating that every aspect of human nature is tainted by sin, though not to the extent that humans are incapable of doing good.

The Role of Free Will
While Original Sin affects human nature, it does not eliminate free will. Humans are still capable of making choices, but their will is influenced by their sinful nature. This tension is evident in Romans 7:18-19 : "I know that nothing good lives in me, that is, in my flesh. For I have the desire to do what is good, but I cannot carry it out. For I do not do the good I want to do. Instead, I keep on doing the evil I do not want to do."

Redemption and Salvation
The doctrine of Original Sin underscores the necessity of redemption through Jesus Christ. Romans 5:18-19 contrasts Adam's disobedience with Christ's obedience: "So then, just as one trespass brought condemnation for all men, so also one act of righteousness brought justification and life for all men. For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous." Through Christ's sacrificial death and resurrection, believers are offered forgiveness and the hope of eternal life.

Baptism and Original Sin
In many Christian traditions, baptism is seen as a means of cleansing from Original Sin. Acts 2:38 records Peter's instruction: "Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit." Baptism symbolizes the washing away of sin and the beginning of a new life in Christ.

Impact on Christian Doctrine
Original Sin has significantly influenced Christian theology, shaping doctrines related to human nature, salvation, and the sacraments. It serves as a reminder of humanity's need for divine grace and the transformative power of the Gospel.