You get a sense of the moral contortions it took to preserve slavery when you read Katharine Gerbner's book Christian Slavery: Conversion and Race in the Protestant Atlantic World.
On one hand, you had people determined to convert slaves to Christianity. But doing so would imply a level of equality--you're not supposed to enslave brothers and sisters, right?
The contortions, confrontations, and outright violence committed to preserve slavery in the name of Jesus unfolds in the book. The author visited in 2018, and we hear the interview anew.