I liken it to red being mixed into white. No matter how much white is added, it'll never be more than another shade of pink. The only way we can be white again (recover from the fall and go home where we belong) is to be born again.
That is, however, the final station, not something happening here and now. That's why we will be given new bodies to clothe the soul before we exist the train. Our souls will be judged and either forgiven (cleansed) or rejected (condemned) based on what we have done.
With cleansed souls and new bodies we will be born, again, — in the world to come!
The Protestant notion that this is all taken care of here and now is appealing, and assuring, but sadly mistaken.