He does because he wants a Cleveland steamer from her
Atticus goes home to get Calpurnia because Aunt Alexandra wants to have a strong female presence in the house while Scout is hosting her missionary tea party. Calpurnia serves as a motherly figure and helps guide Scout through social expectations during the event.
Calpurnia's note to Atticus says that Tom Robinson has been given the death penalty and that there is trouble at the jail. She asks him to come to the jailhouse to help protect Tom from a lynch mob.
We learn that he likes to use words of disappointment as a punishment rather than a physical beating. Atticus is also understanding and he saves Dill from being punished, even though Dill is not his son. He is also kind and loving. (:
Calpurnia went to the courthouse because Atticus asked her to bring Jem and Scout home from the trial of Tom Robinson. She wanted to ensure the safety of the children and make sure they got home safely.
In chapter 12 of "To Kill a Mockingbird," segregation is evident through the division between the white and black communities in Maycomb. We see this when Calpurnia brings Jem and Scout to her black church and they are met with surprise and discomfort from the congregation. The separation of the two races is also highlighted when Calpurnia speaks differently at the church and when she returns to the Finch household.
Calpurnia has come to court to tell Caesar to stay home and not go to the Senate because she had a dream warning of his impending assassination.
Atticus comes home early during the missionary circle because he receives a phone call from the sheriff informing him about Tom Robinson being moved to the Maycomb County jail. Atticus is concerned for Tom's safety as there are rumors of a lynch mob forming.
Calpurnia permits Scout to enter the kitchen to see her aunt, Alexandra. This is significant because Calpurnia usually maintains a strict division between the kitchen, where she works, and the rest of the Finch household.
Walter Cunningham visits the Finches in Chapter 3 of "To Kill a Mockingbird." He is invited to lunch at the Finch household by Scout's father, Atticus Finch. During the visit, Scout learns about the importance of empathy and understanding others' perspectives.
Jem and Scout visit Miss Dubose in Chapter 11 of "To Kill a Mockingbird." Miss Dubose is an irritable neighbor who frequently criticizes Atticus and his legal work. Jem visits her as part of a punishment from Atticus.
Aunt Alexandria believes that Calpurnia's presence is hindering Scout and Jem's moral upbringing. She thinks sending Calpurnia away will help instill her own values in the children. The metaphor of "killing a mockingbird" suggests that Aunt Alexandria wants to remove any influences that she deems as harmful.
Scout intervenes in the mob that surrounds Atticus outside the jail in "To Kill a Mockingbird" in Chapter 15. She recognizes Mr. Cunningham and engages him in conversation, reminding him of his humanity and leading to the dispersal of the mob.
Chapter 347