Miss Maudie explains Atticus's statement to Scout by saying, "Mockingbirds don't do one thing but make music for us to enjoy . . . they don't do one thing but sing their hearts out for us. That's why it's a sin to kill a mockingbird."The mockingbird most obviously represents the innocent who is not protected by society. Just as a careless shooter might hurt an innocent mockingbird, so are innocent people hurt by those who are careless or who have evil intentions. Two of the major "mockingbirds" in the novel are Boo Radley and Tom Robinson.

Jem learns that Mrs. Dubose has a chronic and painful medical condition, his attitude changes. Atticus says she is the bravest person he knows. She has been managing the condition with morphine and has become addicted. The morphine has terrible side effects. Since her condition is terminal, she wants to die with dignity without the morphine. This is why Atticus says she is the bravest person he knows, and Jem learns a lesson in courage.

Scout makes the men realize the human in themselves and in others. Her words of human warmth make the lynch mob leave because they know deep down inside that they are monsters for attempting to harm or kill another human being.

The turnout for the trial shows how humans are curious. Even though they know what will happen to Tom Robinson, some show up with with hope of Tom being declared innocent and others wanting Tom to be killed. Human nature is drawn to things that are not normal—especially bad things that take place in society. Everyone was out to see Tom get sentenced to