In To Kill a Mockingbird, Harper Lee portrays human dignity through the choices made by the characters. For example, Atticus makes a choice to defend a black man to the best of his ability in spite of many citizens feeling strongly he should do otherwise. Atticus also chooses to look past the hurtful comments he and his children receive as a result of his choice. It is his decision to continue along the path of doing what is right over doing what is comfortable that shows dignity.

In contrast, consider Bob Ewell. His decisions are made in attempts to do what is comfortable and convenient above what is right or true. Upon finding his daughter with Tom Robinson, Bob beats her and blames an innocent man. While Atticus models compassion for his children, Bob Ewell models racism and deceit.

At the end of the story, Sheriff Heck Tate faces a dilemma. He knows the truth about the events with Boo Radley and Bob Ewell. In this case, Sheriff Tate sees a difference between what is right and what is true. Here, human dignity is portrayed through Sheriff Tate's choice to protect Boo.

Atticus Finch is about as dignified as a character as you'll ever see in American Literature.  Atticus defends Tom to the best of his ability even though many people in the town think he shouldn't.  Atticus does the right thing no matter what.  At one point he tells Scout that if he didn't defend Tom, he wouldn't be able to tell Scout and Jem not to something again. 

The answers are related, but distinct. Lee portrays it as everyone's responsibility to fight for human dignity, and indicates that the battle can be fought everywhere and anywhere; human dignity is generated through moral courage and depends on that quality. Whether it is Calpurnia protecting the children at her church or Atticus defending Tom, characters attain dignity not through winning their battles but through standing up for what they know to be right.