The Kite Runner, by Khaled Hosseini, is the story of Amir and his journey from guilt and shame to redemption. In the first six chapters of the book, Amir and Hassan are friends, but their commitments to the friendship are not equal. Hassan is loyal and trustworthy, loving Amir despite Amir's mistreatment of him; Amir, on the other hand, is usually jealous of or arrogant to Hassan and feels no loyalty to him.
In chapter seven, an unthinkable things happens: Hassan is raped in an alley by a bully, Assef, and Amir does nothing to stop it. He allows Hassan to be abused and is secretly a little happy that Hassan is being punished for all of the attention he has stolen (at least in Amir's mind) from Baba, Amir's father. He runs away from the awful scene and says,
[T]he real reason I was running, was that Assef was right: Nothing was free in this world. Maybe Hassan was the price I had to pay, the lamb I had to slay, to win Baba.
Things get even worse in chapter nine when Amir's guilt, shame, and anger are so great that he wants nothing more than for Hassan to be gone. Amir tries several tactics, but none of them work. Finally he frames Hassan by planting a watch and some money under Hassan's bed. Baba is finally forced to ask Hassan directly about the incident.
Baba came right out and asked. “Did you steal that money? Did you steal Amir’s watch, Hassan?”
Hassan’s reply was a single word, delivered in a thin, raspy voice: “Yes.”
I flinched, like I’d been slapped. My heart sank and I almost blurted out the truth. Then I understood: This was Hassan’s final sacrifice for me. If he’d said no, Baba would have believed him because we all knew Hassan never lied. And if Baba believed him, then I’d be the accused; I would have to explain and I would be revealed for what I really was. Baba would never, ever forgive me. And that led to another understanding: Hassan knew He knew I’d seen everything in that alley, that I’d stood there and done nothing. He knew I had betrayed him and yet he was rescuing me once again, maybe for the last time.
Amir wanted to get rid of Hassan, and Baba now sends Hassan away because of Amir's lie. We find out later that Hassan is also Baba's son, so Hassan is being betrayed by both Amir, his brother, and Baba, his father. Despite that, Hassan remains loyal and loving to them both.
The opening lines of the book speak of Amir's guilt and remorse:
That was a long time ago, but it’s wrong what they say about the past, I’ve learned, about how you can bury it. Because the past claws its way out. Looking back now, I realize I have been peeking into that deserted alley for the last twenty-six years.
Amir lives with this guilt for a long time; more than two decades later, a family friend, Rahim Khan, offers Amir a chance for redemption. He wants Amir to come back to Afghanistan to rescue Sohrab, Hassan's son, from an orphanage. Hassan died in another act of loyalty to the family. Amir finally agrees to rescue the boy who, it turns out, is in a much worse place than an orphanage by the time Amir finds him.
That was supposed to be the end of his obligation: Amir would rescue his nephew, Baba's grandson, and leave him with a nice family in Pakistan. Instead, Amir is moved to bring Sohrab back to the United States and raise him as his own son. This act of rescue serves as an act of redemption, both for his own sins and his father's against the true and loyal Hassan.