Romans 5:17 For if, because of one man’s trespass, death reigned through that one man, much more will those who receive the abundance of grace and the free gift of righteousness reign in life through the one man Jesus Christ.
18 Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men.
Why did Adam’s sin affect all who were in Adam? Because God designed it that way. He was our representative; he was acting for us; we were in him when he acted. How could Christ’s death and resurrection affect us? Because He is our representative, He is our head, and when He died and rose again we were in Him. We were in Adam naturally; we were in Christ spiritually. This is why the resurrection is so important. We celebrate the resurrection not merely as a historical fact, but as our resurrection. “I am crucified with Christ, nevertheless I live.” We live in Him.

All in Adam….All in Christ