What a pity that Bilbo did not stab that vile creature, when he had a chance!'Pity? It was Pity that stayed his hand. Pity, and Mercy: not to strike without need. And he has been well rewarded, Frodo. Be sure that he took so little hurt from the evil, and escaped in the end, because he began his ownership of the Ring so. With Pity.
J.R.R. Tolkien, The Fellowship of the Ring
mercy, pity