In Lee's To Kill a Mockingbird, consider the advice Scout and Jem receive from Atticus. What is the most important concept the children are...

Atticus gives his children a lot of advice in Lee's To Kill a Mockingbird. Without knowing what this question is asking specifically, here are a few of the main pieces of advice that Jem and Scout receive from their father. First, Atticus teaches his children about courage when Mrs. Dubose dies. He informs them that Mrs. Dubose overcame an addiction to morphine before she died, and then he gives the following lecture:

"I wanted you to see what real courage is, instead of getting the idea that courage is a man with a gun in his hand. It's when you know you're licked before you begin but you begin anyway and you see it through no matter what. You rarely win, but sometimes you do. Mrs. Dubose won, all ninety-eight pounds of her. According to her views, she died beholden to nothing and nobody. She was the bravest person I ever knew" (112).

The advice from the above passage teaches the kids that courage is not found behind the barrel of a gun; rather, it is found inside each one of us as we fight our inner battles each day. 

Another popular piece of advice that Atticus gives his children is not to take advantage of people, or animals, who are at a disadvantage than they are in life. Atticus says this literally and figuratively when he tells his children the following:

“I’d rather you shot at tin cans in the back yard, but I know you’ll go after birds. Shoot all the bluejays you want, if you can hit ‘em, but remember it’s a sin to kill a mockingbird” (90).

Miss Maudie elaborates on what Atticus means by explaining to the kids that mockingbirds only bring happiness and joy to the world. They don't pester anyone, and they sing pretty songs or all to hear. Therefore, those who shoot mockingbirds are abusing their advantages in life and committing a sin. Figuratively, this advice can be applied to people who don't have the same benefits or advantages as Jem and Scout do in life. For example, Boo Radley possibly suffers from a mental or social illness, so people shouldn't tease or take advantage of him. 

Again, there are many other pieces of advice that Atticus gives his children, but here's one last example for Scout to help her socially:

"First of all, . . . if you can learn a simple trick, Scout, you'll get along a lot better with all kinds of folks. 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" (30).

Scout remembers this counsel at different times throughout the novel. It helps her to be patient with her brother, Jem, as he matures and goes through some confusing times in his life. It also helps her to understand Mr. Cunningham and Boo Radley better as she interacts with them as well. Overall, Atticus always seems to have his wits about him, and he is always in control of any situation. Thus, most of what he says can be taken as advice.