To Kill A Mocking Bird: Chapters 10 and 11

In Chapters 10, they talked about shooting mocking birds. Atticus said on page 90, "...remember, it is a sin to kill a mocking bird". I feel as if this quotation has a large significance to the story, especially how the title is To Kill A Mocking Bird. This is also significant, because Scout recalls this is the first time he said something about a sin. In addition, it is very ironic that he is okay with Scout swearing, Jem betting his pants, and both of them misbehaving, but when they kill a mocking bird, it is a sin.