Why Thomas Aquinas and John Calvin suport the idea of original sin?

Thomas Aquinas and John Calvin both supported the idea of original sin because it is a fundamental doctrine in Christian theology that explains the sinful nature of humanity inherited from Adam and Eve's disobedience in the Garden of Eden.

Aquinas, a medieval theologian and philosopher, believed that original sin was necessary to explain the fallen state of humanity and the need for redemption through Christ. He argued that original sin corrupted human nature and inclined people towards sin, making it impossible for them to achieve salvation on their own.

Calvin, a Protestant reformer, also emphasized the doctrine of original sin in his teachings. He believed that all humans are born with a sinful nature due to the fall of Adam and Eve, and that this sinfulness separates them from God. Calvin taught that only through God's grace and the atoning sacrifice of Jesus Christ could people be saved from their sinful state.

Overall, Aquinas and Calvin supported the idea of original sin because they believed it was essential for understanding the human condition and the need for salvation through Christ.