Forgiveness Ideas about forgiveness permeate The Kite Runner.
Hassan's actions demonstrate that he forgives Amir's betrayal, although Amir needs to spend practically the entire novel to learn about the nature of forgiveness.
For the first time, the theme of loyalty comes to its prominence in novel’s scene when, while trying to defend Amir, Hassan aims his slingshot at Assef: “I turned and came face to face with Hassan’s slingshot…
Hassan held the slingshot pointed directly at Assef’s face” (21).
But doing this clearly does nothing toward redeeming himself, and thus his guilt endures.
That is why he still cringes every time Hassan's name is mentioned.
In his letter, he asks Amir to forgive him for keeping Baba's secret but also writes explicitly "God will forgive." Rahim Khan is confident that God will forgive all transgressions, and he encourages Amir to do so, too.
Rahim Khan understands that it is God who readily forgives those who ask for forgiveness, but it is people who have a hard time forgiving.
And, it was not because he was able to subdue Assef physically, but because, for once in his life, Amir did not have any second thoughts, while defying his old arch-enemy, that he ended up achieving a moral victory over Assef: “I don’t know at what point I started laughing… What was so funny was that, for the first time since the winter of 1975, I felt at peace” (147).
The reason why, while fighting Assef, Amir experienced a sensation of inner peace, is that by doing it, he was able to prove its loyalty to Hassan.