In the fourth paragraph, the author says that "that very discontentment which Master Hugh had predicted would follow [his] learning to read had already come” (lines 39–40) primarily to

validate Hugh’s belief about educating enslaved people
support the idea that reading can become a powerful curse
emphasize the wretched condition of being enslaved
highlight the desire for freedom that his reading had inspired
instill the will to learn in other enslaved people