In 1972, Yale professor Sydney Ahlstrom published a remarkable book entitled, A Religious History of the American People. I strongly recommend it.
In his book, Syndey points out that, in 1820, a surprising three-fourths of the anti-slavery societies in American were in the South. Before that, Baptist and Methodist missionaries had been busy preaching the Good News of Jesus Christ there. These missionaries uniformly believed that slavery was no witness to Jesus Christ. As a result, white Christians in the South had formed groups (“societies”) to reflect on slavery and discern how to end it.