The Fall of Adam and the Fall of Mankind

Q. 16: Did all mankind fall in Adam's first transgression?
Answer: The covenant being made with Adam, not only for himself, but for his posterity; all mankind, descending from him by ordinary generation, sinned in him, and fell with him, in his first transgression. (WSC)

Adam was the head of the human race. God made his covenant with humanity by making his covenant with its head, with Adam (Gen. 2:15-17). It is similar to how a king might make a treaty with another nation by making a treaty with its king. In this case, Adam broke the covenant, aligning with the serpent, plunging the whole human race into a war with God. Because he represented his descendants, they all sinned in him and fell with him. His sinful nature would be conveyed to them by natural generation (Gen. 5:3, Ps. 51:5, John 3:6), and his guilt was imputed to them by virtue of the covenant (Rom. 5:12-21). Therefore all are doomed to die, being subject to the curse of the covenant of works.

This relation between us and Adam is taught in Romans 5. Paul says that “sin came into the world through one man, and death through sin, and so death spread to all men because all sinned…” (5:12). He notes that Adam’s transgression was unique, “a type of the one who was to come” (5:14). He sinned as a representative head bringing condemnation and death to all he represented, just as Christ obeyed as a representative head and brought justification and life to all he represented (5:15, 18-19). “For as by the one man’s disobedience the many were made sinners, so by the one man’s obedience the many will be made righteous” (5:19).

Notice how our catechism carefully describes those whom Adam represented: “...all mankind, descending from him by ordinary generation…” What man did not descend from him by ordinary generation? Whom did he not represent? Who did not receive his fallen nature? The one who was conceived by the power of the Holy Spirit in the womb of the virgin Mary and born of her, yet without sin. Jesus Christ is the head of the new humanity, bringing us out of our fallen estate unto life and glory.