Compare Mariam and Laila in A Thousand Splendid Suns

In Khaled Hosseini's A Thousand Splendid Suns, Mariam and Laila are the two female protagonists, and readers hear each of their stories alternately. We first learn of Mariam's childhood with a single mother who bore her of a wealthy man who already has a wife and children. Mariam grows up poor and has a limited education focused on religion. After her mother commits suicide, Mariam insists on being taken in by her father who swiftly marries her off to an older widower, Jalil. Mariam is devastated but has no choice in the matter. She is completely unsatisfied by the marriage but must learn to keep house and cook to Jalil's specifications. Mariam briefly hopes for a child to assuage her loneliness, but after losing a pregnancy, she eventually must accept that she will not become a mother.
Laila, on the other hand, is educated and has fairly liberal-minded parents. Her parents are tragically killed in a bombing and Laila is seriously injured. Jalil takes her in and he and Mariam nurse her back to health. He then takes her as a second wife. At first, Mariam is very resentful of Laila, especially because Jalil verbally abuses Mariam for being older, less beautiful, and unable to bear children. Laila has two children (though one is fathered by her boyfriend and not Jalil), and Mariam bonds with the daughter. This brings Mariam and Laila closer and forges a bond that eventually leads Mariam to kill Jalil to protect Laila.
Naturally, her upbringing makes Laila less submissive and she fights Jalil's oppression on occasion. In one instance, he nearly beats her to death. To save Laila, Mariam kills Jalil, and she takes the fall for the entire family by going to prison while Laila and the children flee Kabul with Laila's former boyfriend and true love.
The women are not at all similar in their upbringings but they end up bonding over their mutual oppression. They form a relationship that is so strong one woman is willing to sacrifice her life for the other. Hosseini's novel illustrates how the hardships of the women's lives allows them to form compassion and empathy for one another; their bond is much stronger than the hate and abuse perpetrated upon them.