What passages prove that Atticus follows the Golden Rule in Harper Lee's To Kill a Mockingbird?
The Golden Rule teaches that we should "do unto others as [we] would have them do unto [us]," which means that we should treat others in the exact same way we would want to be treated ourselves ("The Golden Rule," Internet Encyclopedia of Philosophy). It takes a great deal of kindness, compassion, and understanding to be able to follow the Golden Rule. We cannot follow it if we allow ourselves to judge others based on prejudices because, in seeing people through prejudiced eyes, we treat them unfairly. Only the kind and compassionate person is able to see another person without prejudice, thereby being able to clearly see the person's wants, needs, and even motives for actions. In clearly seeing the wants, needs, and motives of another person, we are able to act in ways that benefit rather than harm the person and thereby act based on the Golden Rule. In Harper Lee's To Kill a Mockingbird, Atticus is characterized as the type of kind, compassionate, unprejudiced person who follows the Golden Rule by acting in ways that strive to benefit others.
One clear moment in which Atticus expresses his belief in the Golden Rule is after Scout's first day of school. Scout is very disappointed with her first day because she has been forbidden to read and write and got into trouble. Atticus explains that she wouldn't have gotten into trouble if she had only been able to see the situation from Miss Caroline's perspective:
First of all, ... if you can learn a simple trick, Scout, you'll get along a lot better with all kinds of folks. You never really understand a person until you consider things from his point of view-- ... --until you climb into his skin and walk around in it. (Ch. 3)
Atticus's lesson to Scout is a mantra he lives by daily. Seeing things from others' perspectives is Atticus's way of following the Golden Rule because all people want their own perspectives understood, and only those who are able to feel compassion for others are truly able to see things from others' perspectives.