Amir: Amir's attitude toward Islam changes throughout the novel. In the beginning as he listens to the mullahs (religious teachers) at school, he seems to weigh their teachings and checks them against what Baba says or does. After he betrays Hassan, Amir distances himself from his god and religion because of his guilt. Near the end of the novel, after Amir has redeemed himself and rescued Sohrab, he prays for the first time in many years and begins to reestablish his relationship with Islam.
Baba: Baba's view of his religion is much more pragmatic than some of the other characters'. When Amir questions Baba about whether drinking alcohol is a sin (that is against Islamic law), Baba tells Amir that the only sin is theft--this seems to be a code of ethics that Baba has developed himself, one which is not based on any strict adherence to a particular religion. While Baba appears to go to religious services and follow Afghan customs when he is in the States, religion never really plays a significant role in his life.
Hassan: Although Hassan practices a different for of Islam than Baba and Amir (he's a Shiite Muslim), his relationship with his religion is much more personal. Hassan is naturally a kind and loyal character, so he naturally has no problem following the customs of his religion and practicing a moral lifestyle.
The Characters in the book "The Kite Runner" have different attitudes about religion. Baba, Amir's father scoffs at religious Zelots and fears that they will bring down his country. When Amir is taught Islam in the fifth grade and tries to share what he has learned with Baba, his father brings him down.
"You’ll never learn anything of value from those bearded idiots."
Rahim Khan is more spiritual than Baba. He may have drank and did not say a lot in the early years about his faith, but as he nears his death he has come to his faith as a Muslim. He goes to worship when he feels well enough. He asks Allah to forgive him when he speaks of things that he wish that he had done differently.
"Then I would pray namaz, cook something, eat, read some more, pray again, and go to bed."(203)
Assef is Taliban. He follows the doctrine of the religious zealots but is basically a sadist. He is the enemy through-out the book.
Hassan, Amir's half brother, is more spiritual than Amir. He practices the traditions of his religion such as wearing black for forty days after he learns of Baba's death from Rahim. When Hassan's son is born he hands him to Rahim to sing the birth prayer song.
"He handed him to me and I sang the prayer of Ayat-ul-kursi in that little boy's ear."(211)
Amir had become Westernized after he and his father had moved to America. He tried hard to leave all that was Afghanistan behind him. He left his faith as well. After he saves Hassan's son, he returns to his faith. He creates a makeshift prayer rug on the floor and bows to Allah.
"I throw my makeshift jai-namaz, my prayer rug, on the floor and I get on my knees, lower my forehead to the ground, my tears soaking through the sheet. I bow to the west. Then I remember I haven't prayed for over 15 years."(345)