How does Lee's narrative voice affect her exploration of the ideas and events in To Kill a Mockingbird? I have two ideas which are Scout's innocence and ignorance. I'm not sure what else there is to add. Also, could injustice be one or does that link into ignorance?
Scout is the narrator. She relates the events of three summers from her childhood. As an older woman, she has the ability of hindsight. In other words, she can look back (with more wisdom) and explain how she came to learn about injustice and prejudice. But she (Lee or the narrator) does rely on framing the events in the eyes of Scout as a child. In this way, Lee can explore Scout's ignorance and innocence but with the added benefit of an adult looking back on her life.
Scout is precocious (smart for her age), so the blending between her childish innocence and the narrator's adult storytelling works very well. In Chapter 21, right before Tom's guilty verdict is announced, Scout recalls something Jem told her and, with great innocence and optimism only a child can envision, she tries to come up with a way to help Tom:
I remembered something Jem had once explained to me when he went through a brief period of psychical research: he said if enough people—a stadium full, maybe—were to concentrate on one thing, such as setting a tree afire in the woods, that the tree would ignite of its own accord. I toyed with the idea of asking everyone below to concentrate on setting Tom Robinson free, but thought if they were as tired as I, it wouldn’t work.
As idealistic as it is, there is also some wisdom to this notion. If enough people actually put forth concentrated thought and effort (such as the jury) in seeking the truth of the trial, then Tom would have been set free. Lee uses Scout's childish innocence to make a dramatic point. In showing Scout's innocence, Lee also shows Scout's wisdom and her ability to see the world without racist lenses. Examples like these suggest that there is wisdom as well as ignorance in the innocent way that children think.