Final answer:
Mr. Shelby agreed to sell Uncle Tom and Young Harry due to financial difficulties, highlighting the dehumanizing aspects of slavery and its impact on families.
Step-by-step explanation:
In Uncle Tom's Cabin, Mr. Shelby agreed to sell Uncle Tom and Young Harry to the slave trader Haley due to economic hardships. Despite his seeming reluctance, Mr. Shelby's decision is driven by financial necessity; his slaves are a representation of his wealth and social status. This heart-wrenching story, penned by Harriet Beecher Stowe, served as a poignant critique of slavery, illustrating how the institution dehumanized both the enslaved and the enslavers, and how it tore apart families. Additionally, it played a significant role in bolstering the abolitionist movement by bringing the moral and familial implications of slavery into everyday conversation among Northerners.