"There is only one sin, only one. Every other is a variation of theft." In The Kite Runner, who says this, what is the explanation?

This statement was made by Baba to Amir. Amir was informing the reader about the conditions before the Taliban took control of Afghanistan. People in Afghanistan enjoyed extensive freedoms back then. At the time, drinking was not a crime, but those who partook of liquor did so in private, out of respect.

This led to a conversation in the study between Baba and Amir. Amir was talking about what he learned from Mullah Fatiullah Khan,...

This statement was made by Baba to Amir. Amir was informing the reader about the conditions before the Taliban took control of Afghanistan. People in Afghanistan enjoyed extensive freedoms back then. At the time, drinking was not a crime, but those who partook of liquor did so in private, out of respect.

This led to a conversation in the study between Baba and Amir. Amir was talking about what he learned from Mullah Fatiullah Khan, who was guiding his religious studies. At the time of their conversation, Baba was drinking whiskey and Amir was reiterating what the Mullah taught about the consequences of drinking. To this effect, Baba decided to explain to Amir his version of sin.

Baba informed Amir that there was only one sin, that of theft. Every other sin was a variation of theft. He further explained that, when an individual kills a man, they rob a life, they rob the wife’s right to a husband and the children’s right to a father. He stated that a lie robs a person's right to the truth and when a person cheats they steal the right to fairness. To this end, Baba concluded that there was nothing worse that stealing.

"There is no act more wretched than stealing, Amir," Baba said. "A man who takes what's not his to take, be it a life or a loaf of naan... I spit on such a man. And if I ever cross paths with him, God help him. Do you understand?"