In chp 11 of "To Kill a Mockingbird" explain the reason why Atticus sends Jem to see Mrs. Dubose and why he is later sent to read to her.
Atticus feels that Jem can learn a lesson from the surly Mrs. Dubose. The reasons that he gives originally for sending Jem are a bit different than the reason he gives after Jem is done. Originally, Jem is sent to apologize to her for destroying her flowers, because "to do something like this to a sick old lady is inexcusable." So, Jem goes down to see her and apologize. But when he comes back he confesses to Atticus that "she wants me to read to her", and Atticus says that's a good idea.
Later, after her death, Atticus reveals that "If you hadn't fallen into her hands, I'd have made you go read to her anyway" in order to teach him what true courage was: "It's when you know you're licked before you begin but you begin anyway and you see it through no matter what." Atticus thought that Mrs. Dubose was a great lesson in bravery, as she vowed to break her morphine addiction in her last days. He saw a great opportunity to teach Jem about courage, and so he took it.