“…many Methodist preachers, taken from comparative poverty, not able to own a negro, and who preached loudly against it, improved, and became popular among slaveholders; and many of them married into those slaveholding families, and became personally interested in slave property (as it is called). [SIC] Then they began to apologize for the evil; then to justify it, on legal principles; then on Bible principles; till lo and behold! it is not an evil, but a good! it is not a curse, but a blessing! till really you would think, to hear them tell the story, if you had the means and did not buy a good lot of them, you would go to the devil for not enjoying the labor, toil, and sweat of this degraded race …”
– from Autobiography of Rev. Peter Cartwright, The Backwoods Preacher, ed. Strickland (1856).
UPDATE: To Discover a Kinsman in You flowed from Cartwright's surmise, and the first comment following below.