Jem is four years older than Scout, but for the most part, he is a protective older brother. Sometimes he takes advantage of Scout - making her bring him things to eat and read in his tree house - but overall, he protects her. He is an adventurous boy and enjoys the excitement of the plan to make Boo Radley "come out" but he senses when he has gone too far. Because he is older than Scout, he is more sensitive to the Tom Robinson affair and reacts impulsively and with anger at Mrs. Dubose' comment that Atticus defends "niggers." In this way, of course, he differs from his father. Atticus is not impulsive. He carefully considers everything and he is wise. He has an excellent reputation in town and he is modest and humble. One gets the idea that Jem may grow up to be Atticus some day.
One thing the two males do share in common is courage. Atticus exhibits his courage by agreeing to defend Tom and then following through with everything that entails, including standing up to the townspeople. Jem exhibits his courage at the end when Bob Ewell attacks him and Scout on their way home from the school play. Another thing the two males share is their ability to be peacemakers. Jem is always intervening on Scout's behalf when she gets into fights. He pulls her off Walter and explains to Walter that Scout won't hurt him. Atticus also is a peacemaker. Not only with his profession, but with his family. He wisely trains Scout to walk in the skin of others so that she, too, can see things from another's point of view.
Harper Lee beautifully uses dialogue to develop her characters. You can find examples of this on almost every page of the novel by reading what the characters say. Also, since Scout is narrating the story as an adult, she has the advantage of not only telling the story but of interpreting the events of the past, so Lee skillfully combines the role of omniscient narrator with that of first person narrative.
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