Final answer:
The mockingbird in Harper Lee's novel symbolizes innocence and the idea that harming innocent beings, who cause no harm to others and only contribute positively to the world, is wrong. This symbolism is extended to characters like Tom Robinson and Boo Radley, who are metaphorical mockingbirds within the story.
Step-by-step explanation:
In Harper Lee's novel To Kill a Mockingbird, the mockingbird symbolizes innocence and purity. It represents beings that bring only positivity into the world, like music from the birds, without causing any harm. When the character suggests that it is a sin to kill a mockingbird, this carries the metaphorical weight that harming innocent people or creatures who do not cause harm to others is morally wrong. The mockingbird, therefore, is a symbol of innocence, goodness, and the nonmaterial value they add to life.
The symbolic meaning expands beyond the literal bird to encapsulate characters in the novel, such as Tom Robinson and Boo Radley, who are symbolic mockingbirds due to their kindness and vulnerability. Their stories highlight the sin of harming those who are innocent and whose existences are beneficial or at least not harmful to others.