"There's some folks who don't eat like us," she whispered fiercely, "but you ain't called on to contradict 'em at the table when they don't. That boy's yo' comp'ny and if he wants to eat up the table cloth you let him, you hear?"
"He ain't company, Cal, he's just a Cunningham-"
"Hush your mouth! Don't matter who they are, anybody sets foot in this house's yo' comp'ny, and don't you let me catch you remarkin' on their ways like you was so high and mighty! Yo' folks might be better'n the Cunninghams but it don't count for nothin' the way you're disgracin' 'em—if you can't act fit to eat at the table you can just set here and eat in the kitchen!"
Calpurnia sent me through the swinging door to the diningroom with a stinging smack. (3.26-29)
Cal's moral lesson here is to respect people's differences, even if you think you're better than them. And acting like you're better than other people is the surest way to show that you're not. This interaction is an early blow against the stereotype that white people have morals but African-Americans don't—and Cal follows it up with a loving "blow" of her own. There's nothing like a smack to make a lesson hit home, right?
"There are just some kind of men who—who're so busy worrying about the next world they've never learned to live in this one, and you can look down the street and see the results." (5.44)
Miss Maudie's talking about Nathan Radley here, but also about his fellow foot-washing Baptists who think she's going to hell for making her garden pretty. Miss Maudie's no party girl, but she still strikes out at those who think that all pleasure is bad—except for the pleasure they obviously take in judging their neighbors as sinners.
"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." […]
"Atticus, are we going to win it?"
"Simply because we were licked a hundred years before we started is no reason for us not to try to win," Atticus said. (9.16-25)
For Atticus, you have to judge yourself before you can judge anyone else. Or something like that. His own self-respect is bound up with his good morals: if he did something he knew was wrong, even if it was justified, he would lose all moral authority over others.
"Well, most folks seem to think they're right and you're wrong...."
"They're certainly entitled to think that, and they're entitled to full respect for their opinions," said Atticus, "but before I can live with other folks I've got to live with myself. The one thing that doesn't abide by majority rule is a person's conscience." (11.54-57)
Democracy may determine how a group will act, but it can't control what a person thinks: the jury can vote to find Tom guilty, but it can't make everyone in Maycomb believe that he is. (But you think that makes him feel any better?)
"Son, I have no doubt that you've been annoyed by your contemporaries about me lawing for n******, as you say, but to do something like this to a sick old lady is inexcusable. I strongly advise you to go down and have a talk with Mrs. Dubose," said Atticus. "Come straight home afterward." (11.43)
Even when others do things that Atticus would rather eat spiders than do, he still thinks they should be treated with respect. In his moral system, just because Mrs. Dubose strikes out at Jem doesn't mean he's allowed to strike back. Atticus is definitely a New Testament kind of guy, turning the other cheek rather than going after an eye for an eye.
"Link, that boy might go to the chair, but he's not going till the truth's told." Atticus's voice was even. "And you know what the truth is." (15.23)
Atticus knows it's more unlikely than a Lindsay Lohan presidency that Tom will be acquitted, and yet getting the truth out there is still an accomplishment—even if we're not quite sure what it'll accomplish.
"You know the truth, and the truth is this: some N****es lie, some N****es are immoral, some N**** men are not to be trusted around women—black or white. But this is a truth that applies to the human race and to no particular race of men. There is not a person in this courtroom who has never told a lie, who has never done an immoral thing, and there is no man living who has never looked upon a woman without desire." (20.48)
Racism logic fail: Tom is black, black is bad, therefore Tom is bad. Atticus tries to transform it into, "Tom is a man, some men are bad, some men are good, and now listen to the evidence and decide which group Tom belongs to." Convicting Tom because he is black, Atticus argues, would be as silly as convicting him because he is a human being.
"Heck," Atticus's back was turned. "If this thing's hushed up it'll be a simple denial to Jem of the way I've tried to raise him. Sometimes I think I'm a total failure as a parent, but I'm all they've got. 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 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." (30.37)
Here's a new way of looking at parenting: instead of telling your kids not to embarrass you, how about trying not to embarrass your kids? Only, we're not talking about retiring your mom jeans or putting your cellphone in your pocket instead of clipping it to your belt. We're talking about living an upright, honest, and moral life—and that's a lot harder.