There are several ways in which To Kill a Mockingbird teaches these important lessons.
First, it takes courage and grit to stand up for what is right. If the whole town is against you and you are standing up for something that others despise, then you will need grit to persevere. Moreover, to do what is obviously correct is to promote citizenship, that is, to make the world a better place to live. Atticus does this, as he stands up for the right of Tom Robinson.
"If you shouldn't be defendin' him, then why are you doin' it?" "For a number of reasons," said Atticus. "The main one is, if I didn't I couldn't hold up my head in town, I couldn't represent this county in the legislature, I couldn't even tell you or Jem not to do something again…Scout, simply by the nature of the work, every lawyer gets at least one case in his lifetime that affects him personally. This one's mine, I guess."
What is equally impressive is Atticus' social and emotional intelligence. For example, he has compassion on Mayella, as he knows her predicament in life. He writes these insightful words:
“The state has not produced one iota of medical evidence to the effect that the crime Tom Robinson is charged with ever took place. It has relied instead upon the testimony of two witnesses whose evidence has not only been called into serious question on cross-examination, but has been flatly contradicted by the defendant. The defendant is not guilty, but somebody in this courtroom is.
“I have nothing but pity in my heart for the chief witness for the state, but my pity does not extend so far as to her putting a man’s life at stake, which she has done in an effort to get rid of her own guilt."