How do we know the fall of Adam affects all humanity?

The significance of Adam’s fall is foundational to understanding human depravity. Romans 5:12 articulates that 'as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned.' This indicates that through Adam's transgression, sin and death entered into humanity, affecting all descendants. In this way, Adam serves as the representative head of humanity, establishing a theological basis for the need of redemption through Jesus Christ. This doctrine emphasizes the nature of original sin and the universal condition of man in need of salvation, thereby highlighting the redemptive work of Christ as essential.