Where is this line in the book?

[Rían]

Help, please There's a scene that I like in TT, near the end (chpt 30 in the DVD), when Frodo and Sam are talking in the ruins of Osgiliath right after Frodo draws his sword on Sam, then drops it in horror at what he's done to his friend. Frodo says he can't go on, then Sam starts talking about the great stories, and Frodo asks "what are we holding on to, Sam?" and Sam answers "that there's some good in this world, Mr. Frodo, and it's worth fighting for!"

I remember the "great stories" section in the books (but not where it was in the books - anyone remember?), but not Sam's last line - does anyone remember that line? (or maybe it's spoken by someone else?)