From the SugarQuill Boards

17) What was your reaction when you found out that remorse could help put the soul back together? Did you think that it would come up later in the book? Or that maybe Voldemort was capable of showing guilt?

ME: I was frankly - even though I have been advocating that Jo Rowling was writing from a Christian perspective - shocked. Remorse - or as Christians call it, Repentance - is a key ingredient to "salvation." It's not enough that God might want to save people and then take a hike and watch from His Undisclosed Location. No, Christians believe that people play a part in that salvation (well, a problem with that did lead to the Protestant Reformation, but never mind). Repentance and Confession are key ingredients to being saved. That Rowling would extend this tenet (or I might maintain - truth) to Voldemort was simply astonishing. This wasn't just a "vanquish the enemy and triumph" moment. It was an opportunity for transformation for even the worst, which is at the heart of the Gospel (see Paul, who was no friend of Christians and took part in the stoning of Stephen in Acts). We will Harry see extend Grace. Such things do restore the soul, even in real life.

So we have presented to us in Deathly Hallows that the soul is restored through repentance and acts of grace. That just blows my mind.