Harry Potter and the Deathly Hallows
"…It warns in this book how unstable you make the rest of your soul by ripping it, and that's just by making one Horcrux!"
Harry remembered what Dumbledore had said about Voldemort moving beyond "usual evil."
"Isn't there any way of putting yourself back together?" Ron asked.
"Yes," said Hermione with a hollow smile, "but it would be excruciatingly painful."
"Why? How do you do it?" asked Harry.
"Remorse," said Hermione. "You've got to really feel what you've done. There's a footnote. Apparently the pain of it can destroy you. I can't see Voldemort attempting it somehow, can you?" (6.71-73)
"Your point about Wizard dominance being FOR THE MUGGLES' OWN GOOD – this, I think is the crucial point… We seize control FOR THE GREATER GOOD." (18.34)
Three objects, or Hallows, which, if united, will make the possessor master of Death… Master… Conqueror… Vanquisher… the last enemy that shall be destroyed is death…
And he saw himself, possessor of the Hallows, facing Voldemort, whose Horcruxes were no match… Neither can live while the other survives… Was this the answer? Hallows versus Horcruxes? Was there a way, after all, to ensure that he was the one who triumphed? If he were the master of the Deathly Hallows, would he be safe? (22.19-21)