A passage from George R.R. Martin's Song Of Ice And Fire.

Night gathers, and now my watch begins. It shall not end until my death.
I shall take no wife, hold no lands, father no children.
I shall wear no crowns and win no glory. I shall live and die at my post.

I am the sword in the darkness. I am the watcher on the walls.
I am the fire that burns against cold, the light that brings the dawn, the horn that wakes the sleepers, the shield that guards the realms of men.
I pledge my life and honor to the Night's Watch, for this night and all the nights to come.

Books of the series:

1. A Game of Thrones
2. A Clash of Kings
3. A Storm of Swords
4. A Feast for Crows
5. A Dance with Dragons