Mr. Gilmer, the prosecutor, questions Tate, who recalls Bob Ewell saying that Tom Robinson had raped Mayella Ewell. Atticus cross-examines: Tate says the right side of Mayella's face was heavily bruised. Next, Bob Ewell is called to the stand. He is arrogant and unpleasant, and gets reprimanded by Judge Taylor. Chastened, he tells Mr. Gilmer about finding Tom Robinson raping his daughter. Atticus cross-examines: he tricks Ewell into writing his name, which reveals that Ewell is left-handed. Ewell is furious. Jem says: "We got 'em," because a left-handed man is more likely to bruise the right side of someone's face.
Though Jem is growing up, he still has childish beliefs. For instance, he thinks that mere evidence will be enough to exonerate Tom. Of course, in a perfect world Jem's innocent belief would be accurate: evidence would be enough to save Tom. Jem's childish innocence therefore functions as a condemnation of the racist adult society of Maycomb.