Atticus is a true gentleman and Christian. A bit of background first.
According to the book, Bob spit on, cursed, and threatened to kill Atticus. Here is the quote:
According to Miss Stephanie Crawford, however, Atticus was leaving the post office when Mr. Ewell approached him, cursed him, spat on him, and threatened to kill him.
When this happened, Atticus did not flinch. He just stood there and took it. He simply took out his handkerchief and wiped his face. Then he walked away. When Jem found out, he was upset at Bob and how Atticus handled the situation. How can Atticus allow this to happen?
The reader is not left in the dark as to why Atticus did this. Atticus explained his rationale to Jem. Here is what he says:
“He meant it when he said it,” said Atticus. “Jem, see if you can stand in Bob Ewell’s shoes a minute. I destroyed his last shred of credibility at that trial, if he had any to begin with. The man had to have some kind of comeback, his kind always does. So if spitting in my face and threatening me saved Mayella Ewell one extra beating, that’s something I’ll gladly take. He had to take it out on somebody and I’d rather it be me than that houseful of children out there. You understand?”
Atticus handled everything amazingly. He showed incredible patience and compassion. His action was not one based on fear but sacrifice and love for Bob's children. Moreover, he modeled what he wanted his children to learn - the ability to see things from the perspective of another person, that is, the ability to walk in someone else's shoes. Atticus has my respect, and I am sure the respect of many others.