Why does every human being have a fallen sin nature because of Adam?
Adam acted as the federal head of the human race, so when he sinned, his fallen sin nature passed to every human being—Eve, all their children, and everyone born afterward. That is why Scripture says, “as in Adam all die”; all people share Adam’s fallen condition and are subject to death.
Les explains from 1 Corinthians 15:22 that Adam was the federal head of the human race. When Adam sinned, every human being—including Eve, all the children of Adam and Eve, and anyone born since—now has Adam’s fallen sin nature. Therefore, “as in Adam all die.” The verse goes on to say, “even so in Christ shall all be made alive.” Les notes this raises the question of whether the lost will be resurrected, and he says yes: the lost will come out bodily to appear before the great white throne of Revelation 20, then go to their eternal doom bodily with a body fit for the lake of fire, whereas believers will have a body fit for glory.
For as in Adam all die, even so in Christ shall all be made alive.