The Return of the King (The Lord of the Rings, #3)

by J.R.R. Tolkien

As Frodo clung upon his back, arms loosely about his neck, legs clasped firmly under his arms, Sam staggered to his feet; and then to his amazement he felt the burden light.

This is probably my favorite scene in all the book: when Sam literally carries Frodo on his back to get him up Mt Doom. When we help carry others, even when our own pain is great, there is a certain magic that comes to lighten the burden.