The Finch family housekeeper, Calpurnia, teaches Scout many things during the course of To Kill a Mockingbird, but the visit to Cal's church may have been one of the most important. Calpurnia is responsible for teaching Scout how to write in cursive, and the housekeeper gives her advice on how to deal with Jem's growing pains. But when Calpurnia takes the Finch children to the Negro church, she wants them to see how her people worship. Afterwards, as they walk back to the Finch house, Scout asks Calpurnia about the way she talks.
"Cal, why do you talk nigger-talk to the--to your folks when you know it's not right?"
Cal explained that she would feel out-of-place if she spoke the same way at church as she did with the Finches.
"It's not necessary to tell all you know. It's not ladylike--in the second place, folks don't like havin' somebody around knowin' more than they do. It aggravates 'em."
She wants Scout to understand humility--that although knowledge is a good thing, it's not always necessary to show others how much you know.
In the book "To Kill a Mockingbird" Calpurnia is representative of a mother figure for the children. There are two things that are significant that Calpurnia teaches Scout. Walter Cunningham goes to the house for dinner and pours syrup over everything. Calpurnia scolds Scout after she rudely announces that Walter is pouring syrup over everything. Calpurnia is trying to teach Scout to be good to people and not to say rude things.
This is reflected again when Calpurnia takes Scout to her church in the colored community. The church was built by freed slaves. Scout notices that Calpurnia uses different types of speech and communication with her black friends than she does around white people. Once again Scout rudely asks her about it. Calpurnia answers her but also lets Scout know that one can not always say what one wants to say and her behavior was rude.
However, the greatest thing that I believe Calpurnia teaches Scout through her guidance and taking her to the black community is that black people are just like white people. They have families, faith, and dreams. They are a community that works together to survive. She teaches Scout the existence of humanity as being one and not a separate color.