Romans 5:12 Wherefore, 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: 13 (For until the law sin was in the world: but sin is not imputed when there is no law. 14 Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam’s transgression, who is the figure of him that was to come.
Paul is starting one of the most important section of scripture regarding imputation. He begins with the very first imputation. His subject is the imputation of righteousness and therefore our justification. He uses the first Adam to show as a type what the last Adam accomplished. He starts by showing how all the seed of Adam, every person that came after Adam was affected by his sin. The sin that Adam committed passed to all.
Genesis 2:17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
The death promised to Adam for disobedience to God was passed to all his seed. Sin and therefore death passed to all. When Adam sinned, it was as if all sinned. Verse 13 is an objection to this idea saying it is not fair that sin be imputed if there is no law. The evidence that sin was imputed was that even those who lived before the law was given to Moses experienced death. Death was in the world long before the law was given, therefore sin and death were passed to all. Death reigned from Adam to Moses. Death reigns now. Sin has touched all.
Romans 3:23 For all have sinned, and come short of the glory of God;
Adam was a type of Him that was to come. He was a type of Christ. We will see that in the same way Adam affected his seed, Christ will affect His seed. This is the comparison that Paul is showing us. All Adam represented were affected by his actions. In the same manner all that Jesus Christ represented were affected by His actions.