Do you think you would ever be willing to die in someone else’s place? Can you imagine a really good person whose life and lifestyle was so worthy, that you would say “No, let them live. Take me instead”? You might. Although chances are, it would not be the goodness of the other person but your love for them that would cause you to take their place.
But what about stepping up and dying in the place of someone who was really a louse; someone who really deserved to die? What then?
This is a question that Paul is trying to resolve in chapter 5 of his letter to the Romans.