How we cite our quotes: (Part.Chapter.Paragraph)
Quote #4
She would never leave her mark on Mammy's heart the way her brothers had, because Mammy's heart was like a pallid beach where Laila's footprints would forever wash away beneath the waves of sorrow that swelled and crashed. (2.20.23)
Mammy has dedicated her life to the memory of her two sons, Ahmad and Noor. While this might seem heartwarming at first, the result is that she's unable to be there for Laila in the way a mother should be.
Quote #5
Leaving Afghanistan had been unthinkable to her while Ahmad and Noor were still alive. Now that they were Shaheed, packing up and running was […] a betrayal, a disavowal of the sacrifice her sons had made. (2.21.56)
Again, Mammy's love for her sons is so strong that it actually hurts the people around her. Ironically, her dedication to her family is exactly what puts them in greater danger.
Quote #6
"It's my father I can't leave," Laila said. "I'm all he has left. His heart couldn't take it either."
Tariq knew this. He knew she could not wipe away the obligations of her life any more than he could his. (2.25.50-51)
Family is hugely important to the characters of A Thousand Splendid Suns. Just like Babi is dedicated to Mammy, Laila is dedicated to Babi. These bonds are the most important things in the characters' lives.