What is the significance of the memories Amir recalls as he witnesses Hassan’s rape? What do they suggest about his feelings or thoughts?

Amir's memories allude to the way he felt about Hassan..... all of his guilt over the rape came down to Hassan's being a "sacrificial lamb"....... a Hazzarra..... better you than me. His feelings of guilt and emotion leave him no question as to whether or not he has a choice in saving Sohrab. Sohrab is his redemption..... the only way he can assauge the guilt he's carried his entire life.