Instead of condemning slavery outright what did James Henley Thornwell preach?

James Henry Thornwell was a Presbyterian preacher and religious writer born in South Carolina in 1812. He became prominent in the South and had a prominent role in establishing the Southern Presbyterian Church. He didn't condemn slavery outright or any other way because he was an advocate of slavery. In 1850 he characterized the Abolitionists in the conflict over slavery as atheists, socialists, communists, red republicans, Jacobins and characterized supporters of slavery as friends of order and regulated freedom.

He should be contrasted to Albert Barnes at the related question link.