One of the themes of "A Rose for Emily" is the constant struggle between the past and the present. Emily cannot let go of the past, especially the attitudes and customs of her father's generation. She believes in the importance of heredity and aristocracy and is holding on to the antebellum beliefs of the past. Colonel Sartoris's decree that Emily is exempt from paying taxes in Jefferson give Emily a license to live as if she is above everyone. Sleeping with Homer's dead body symbolizes Emily's inability to let go of the past and embrace the new ideas of the next generation.
Faulkner gradually reveals this theme through the attitudes of the characters. Emily treats her servant Tobe almost as if he is a slave. The townspeople are just as bad as Emily because they allow her to behave the way she does. When Emily asks for rat poison the clerk allows her to buy it even though she never states its purpose when she is asked. Although the town officials ask Emily to pay taxes, they never try hard enough to succeed. The subtle passivity and backwardness of the town allow Emily to grow stranger as the story progresses, building to the shocking climax of discovering that Emily had been sleeping next to Homer's dead body for years.