What is the concept of "original sin" in Christianity?

The concept of "original sin" in Christianity specifically refers to the fallen state of human nature that is believed to be inherited from Adam and Eve, the first humans according to biblical tradition. This doctrine suggests that as a result of their disobedience to God – eating the forbidden fruit – sin entered into the world and affected all of humanity. This inherited condition means that all people are born with a propensity to sin and are in need of salvation, which is a foundational idea in Christian theology.

This understanding emphasizes the broken relationship between God and humanity due to this intrinsic sinfulness, which is part of the reason Jesus Christ's redemptive sacrifice is seen as necessary. The concept underlines the importance of grace in Christian doctrine, highlighting that salvation cannot be achieved solely through human efforts but is instead a gift from God due to His grace.

The other options do not accurately reflect the doctrine of original sin. The notion of inherent goodness contradicts the belief in original sin, while the idea of human perfection is fundamentally at odds with the concept of a fallen nature. Additionally, considering punishment for Cain’s sin does not relate to the broader theological implications of original sin, which pertains to the state of humanity stemming from Adam and Eve's actions.