How did Scout and Jem learn about the sin of killing a mockingbird and how did their lesson relate to Tom, Arthur, or both?
Uncle Jack bought Scout and Jem air rifles. In this context, Atticus gave them a stern warning. He stated that they could shoot at all the bluejays they wanted, but they should never shoot a mockingbird. To do so would be a sin. In fact, these words are so memorable that Scout remembers that this was the first time Atticus called something a sin. Here is the quote:
Atticus said to Jem one day, “I’d rather you shot at tin cans in the back yard, but I know you’ll go after birds. Shoot all the bluejays you want, if you can hit ‘em, but remember it’s a sin to kill a mockingbird."
That was the only time I ever heard Atticus say it was a sin to do something, and I asked Miss Maudie about it.
As the story progresses, both Scout and Jem are able to relate this concept to life. It is a sin to kill a mockingbird, because all they do is good things. Therefore, it is a sin to harm anyone who only does good. Tom Robinson is an example. So, when Maycomb hurt him, Maycomb killed a mockingbird. Boo is also a mockingbird. All through the story, he only did good things for the children. Therefore, it is imperative to protect him.