Final answer:
White Southerners learned that educated slaves could lead rebellions, prompting harsher restrictions on black literacy and congregation to sustain the slave system after the Nat Turner Rebellion.
Step-by-step explanation:
The lesson that white Southerners learned from the Nat Turner Rebellion was that literate slaves and free blacks posed a significant threat to the stability of the slave system. Turner's literacy and his religious standing enabled him to interpret the Bible and the egalitarian messages of the Second Great Awakening to advocate for rebellion, which led to the deadliest slave uprising in the United States. In the aftermath, to prevent similar insurrections, Southern states implemented oppressive laws, such as prohibiting the education of slaves and free blacks and restricting religious assemblies without a licensed white minister present. These measures reaffirmed the commitment to slavery and increased control over the African American population, highlighting the fear of slave uprisings among white Southerners.