Hassan’s cleft lip is one of his most representative features as a child, and it is one of the features Amir refers to most in describing him. The split in Hassan’s lip acts as a mark of Hassan’s status in society. It signifies his poverty, which is one of the things that separates him from Amir, simply because a cleft lip indicates that he and his family do not have the money to fix the deformity. Baba, who is Hassan’s biological father, chooses to pay a surgeon to repair Hassan’s lip as a birthday gift, signifying his secret fatherly love for Hassan. Later, Assef splits Amir’s lip as he beats him, leaving Amir with a permanent scar much like Hassan’s. In a sense, Amir’s identity becomes merged with Hassan’s. He learns to stand up for those he cares about, as Hassan once did for him, and he becomes a father figure to Sohrab. Because of this, it also serves as a sign of Amir’s redemption.
The kite serves as a symbol of Amir’s happiness as well as his guilt. Flying kites is what he enjoys most as a child, not least because it is the only way that he connects fully with Baba, who was once a champion kite fighter. But the kite takes on a different significance when Amir allows Hassan to be raped because he wants to bring the blue kite back to Baba. His recollections after that portray the kite as a sign of his betrayal of Hassan. Amir does not fly a kite again until he does so with Sohrab at the end of the novel. Because Amir has already redeemed himself by that point, the kite is no longer a symbol of his guilt. Instead, it acts as a reminder of his childhood, and it also becomes the way that he is finally able to connect with Sohrab, mirroring the kite’s role in Amir’s relationship with Baba.
In Islam, as in Christianity, the lamb signifies the sacrifice of an innocent. Amir describes both Hassan and Sohrab as looking like lambs waiting to be slaughtered. Amir says this during Hassan’s rape, noting that Hassan resembled the lamb they kill during the Muslim celebration of Eid Al-Adha, which honors Abraham’s near sacrifice of his son for God. Similarly, he describes Sohrab as looking like a slaughter sheep when he first sees Sohrab with Assef. Assef and the others had put mascara on Sohrab’s eyes, just as Amir says the mullah used to do to the sheep before slitting its throat. Both Hassan and Sohrab are innocents who are figuratively sacrificed by being raped, but these sacrifices have very different meanings. In Hassan’s case, Amir sacrifices him for the blue kite. But in Sohrab’s case, Amir is the one who stops his sexual abuse. In this context, sacrifice is portrayed as the exploitation of an innocent.