In To Kill a Mockingbird, Harper Lee’s creates a strong character in Atticus Finch—a good father and a decent man. While his methods are non-traditional (to Aunt Alexandra's chagrin), Atticus sets up guidelines that he expects the kids to follow. His actions are courteous and honorable. This method of child-rearing is so effective that the children would rather be smacked than stare into the face of Atticus’ disappointment in them.
Atticus is a man of positive action. When the lynch mob shows up at the jail to take Tom Robinson, Atticus is armed with nothing more than a chair, a light and a newspaper. He believes not in force, but in reasoning with people.
Atticus speaks to Heck Tate at the end of the story when Atticus believes Jem has stabbed Bob Ewell and that Heck is trying to fix things so Jem won’t get in trouble.
I don’t want [Jem] growing up with a whisper about him, I don’t want anybody saying, ‘Jem Finch…his daddy paid a mind to get him out of that.’
If this thing’s hushed up it’ll be a simple denial to Jem of the way I’ve tried to raise him...Before Jem looks at anyone else he looks at me, and I’ve tried to live so I can look squarely back at him…if I’ve connived at something like this, frankly I couldn’t meet his eye, and the day I can’t do that I’ll know I’ve lost him. I don’t want to lose him and Scout, because they’re all I’ve got.
With Mrs. Dubose, we also see that Atticus is a man who lives by example. Though Mrs. Dubose is nasty and insulting, Atticus is never anything but a gentleman. Atticus practices the biblical maxim of “turn the other cheek.” He acts this way regardless of someone's personal circumstances, and expects his children to do so also. It is Atticus that suggests that his children (specifically Scout) put themselves in another’s place:
You never really understand a person until you consider things from his point of view […] until you climb into his skin and walk around in it.
Atticus has demonstrated strength and self-restraint in all that he does: with Mrs. Dubose, with Alexandra, and especially in the courtroom defending Tom Robinson. He does so even when dealing with criticism from the community not for taking on Tom Robinson's case, but actually trying to win the case for a black man.
It is Stephanie Crawford who brings the details of Atticus' confrontation with Bob Ewell to his family. Ewell sees Atticus on the street after the court case has ended, and spits in his face. Stephanie reports that...
...Atticus didn't bat an eye, just took out his handkerchief and wiped his face and stood there and let Mr. Ewell call him names...
He cursed Atticus and threatened to kill him. When Ewell asked Atticus if he was too proud to fight, Atticus responded:
"No, too old," put his hands in his pockets and strolled on.
He did not raise his voice or get angry. When Atticus relates the events himself, he approaches it all without rancor; he does so seemingly with dry humor:
I wish Bob Ewell wouldn't chew tobacco...
Atticus is the story's moral compass, especially for his children. He leads by example. In not raising voice or hand in anger, he demonstrates that there is strength in refraining from violence (something Scout has a propensity for). Atticus lives what he preaches, not just for himself, but to raise strong children who show tolerance for others. They learn it is better to simply walk away, and that they "win" by rising above a need to get even.