Final answer:
Calpurnia teaches Scout a lesson about empathy and respect when Walter Cunningham comes over for lunch, highlighting the importance of accepting others' differences and habits without judgment.
Step-by-step explanation:
The lesson that Calpurnia teaches Scout when Walter Cunningham comes for lunch in To Kill a Mockingbird Chapter 3 revolves around the principles of empathy, respect, and understanding of others' differences. When Scout criticizes Walter for pouring syrup over his food, Calpurnia takes her aside and scolds her for her behavior. Calpurnia emphasizes that every individual has different habits and that it is not Scout's place to judge them based on her own standards, especially when they are guests in her home.
Through this experience, Calpurnia teaches Scout a critical life lesson about hospitality, tolerance, and the importance of respecting others' perspectives, which aligns with one of the overarching themes of the novel: to practice understanding and not judge others based on superficial differences. It's a poignant moment where the theme of walking in someone else's shoes is exemplified through Calpurnia's wisdom and Scout's learning process.