What is a quote from Harper Lee's To Kill a Mockingbird that depicts Atticus treating his children like adults while he teaches them a lesson?

In Chapter 23, Scout asks Atticus what will happen if Tom Robinson loses his appeal. Atticus tells Scout that Tom will go to the electric chair unless the Governor "commutes his sentence." Jem comments that it isn't right to sentence Tom to death, and Atticus tells him that rape is considered a capital offense in Alabama. When Jem mentions that the jury could have given Tom twenty years, Atticus explains that because Tom is black, it was either straight acquittal or nothing. Jem then says that he thinks rape shouldn't be a capital offense, and Atticus disagrees with him. Atticus tells his children that he doesn't have any "quarrel" with the rape statute, but does have deep misgivings about the state administering the death penalty based on purely circumstantial evidence. He looks at Scout, and reiterates his statement in simpler terms by saying, "before a man is sentenced to death for murder, say, there should be one or two eye-witnesses" (Lee 294). Atticus goes on to say that without an eye-witness there is always a doubt. Jem gets upset and comments that the state ought to do away with juries. Atticus responds by explaining that the men on the jury were typically reasonable men, but their prejudice would not allow them to be fair even if they tried. He goes on to say,

"you'll see white men cheat black men every day of your life, but let me tell you something and don't you forget it---whenever a white man does that to a black man, no matter who he is, how rich he is, or how fine a family he comes from, that white man is trash" (Lee 295).

This conversation that Atticus has with his children depicts how he speaks to them as adults by discussing serious subjects regarding the penalty for rape, the justice system and racial prejudice in a straightforward manner. He explains the intricacies of the judicial process with Jem and Scout, as well as how the jury's prejudice affected their decision. The children learn that the death sentence should not be granted based on circumstantial evidence alone and that individuals who treat African Americans unfairly are essentially immoral people.