Calpurnia is more than just a housekeeper to the Finch family. She also serves as a surrogate mother to Jem and Scout. Calpurnia is a mother herself: She has raised Zeebo (a city worker), who is one of the few members of the church who can read. She has assisted the Finch children in their education, teaching Scout how to write cursive. When Jem and Scout decide to accompany Calpurnia to her church, she is careful to dress them in their finest clothes and wishes them to be on their best behavior. Their actions reflect upon her, and she is anxious that they impress her friends in the congregation. She lectures them on many things, and when Scout and Jem begin to drift apart, Calpurnia spends more time with Scout, explaining to her that Jem is growing toward adulthood. At times Calpurnia seems overly strict to Scout, but it is because she knows that the children need a bit more guidance and structure than Atticus is willing to give them. The trip to the church gives the children a better glimpse into the real Calpurnia, whose work ethic and Christian values are passed on to her charges whenever possible. Atticus realizes her importance in the household; when sister Alexandra attempts to force Calpurnia out, Atticus puts his foot down. Calpurnia is family, and he knows that his children thrive on her continuing presence.