In this chapter, Scout Finch recounts her continued struggles with her school life, particularly her interactions with her classmates. After a confrontation with her teacher, Miss Caroline, Scout finds herself frustrated and confused. The conflict escalates when Scout gets into a fight with Walter Cunningham, a boy from a poor family. This altercation begins when Scout tries to explain to Miss Caroline why Walter will not accept a quarter for lunch; his family does not have the means to pay it back. In a moment of anger, Scout lashes out at Walter, which leads to her punishment.

Later, Scout's older brother, Jem, intervenes and invites Walter to their home for lunch, demonstrating a key theme in the book: empathy. During the meal, the Finch family’s housekeeper, Calpurnia, scolds Scout for her rude behavior toward Walter when she criticizes his eating habits. This incident serves as a pivotal teaching moment, as Atticus Finch, Scout's father, emphasizes the importance of understanding others. He explains that to truly know a person, you must first walk in their shoes, highlighting the moral lessons that will guide Scout and Jem throughout the story.

The chapter not only focuses on the social dynamics of Maycomb but also introduces the concept of class disparity, as Walter's family's financial struggles contrast sharply with the Finch family's situation. Atticus's teachings aim to instill compassion in his children, urging them to look beyond their immediate perceptions and judgments. This lesson is further emphasized when Scout realizes that Walter's circumstances are beyond his control, and her understanding of social complexities begins to deepen.

In summary, Chapter 3 of 'To Kill a Mockingbird' explores the themes of empathy, social class, and moral growth through Scout's interactions with Walter Cunningham and the lessons imparted by Atticus. It sets the stage for Scout's development as she learns to navigate the complexities of her environment in Maycomb, Alabama.