Who tells Jem he has to read to Mrs. Dubose every night?

In chapter 11, Jem and Scout walk to the store and get harassed by their racist, ornery neighbor, Mrs. Dubose. Mrs. Dubose tells Scout that she will end up waiting tables at the O.K. Café before telling the children, "Your father’s no better than the niggers and trash he works for!" (Lee, 105). After listening to Mrs. Dubose criticize Atticus, Jem becomes infuriated, clenches his fists, and briskly walks to the store. On their walk back home, Jem takes Scout's new baton and uses it to destroy Mrs. Dubose's camellia bush. Later that day, Atticus returns home, reprimands Jem for ruining Mrs. Dubose's flowers, and makes him apologize to her. When Jem returns home from apologizing to Mrs. Dubose, he tells Atticus that she wants him to read to her every afternoon and on Saturdays. When Jem asks Atticus if he has to read to Mrs. Dubose, Atticus responds by telling his son, "Certainly" (Lee, 109). Atticus does Mrs. Dubose a favor by making Jem read to her each afternoon, which occupies her mind long enough to break her morphine addiction so that she can die a free woman.