How did Frederick Douglass think religious beliefs affected the way that people treated slaves?

Douglass
felt and stated strongly that Christianity made slave owners more barbaric in their behavior
than they were before they became Christians. He uses his master, Captain Auld, as an example.
He states that when Auld went to a Methodist camp meeting and had a conversion experience,
Douglass held out a faint hope he would be freed. Instead, Douglass says, Captain Auld's
conversion made him more "cruel and hateful." Before he became a Christian, Auld had
only his "own depravity" to sustain him. Once he became a Christian, however, he had
the entire Southern church institution behind him, sanctioning his cruelty. For example, Auld
would cite a Bible verse to justify the savage beating of a female slave. As Douglass puts
it:

I have seen him tie up a lame young woman, and whip
her with a heavy cowskin upon her naked shoulders, causing the warm red blood to drip; and, in
justification of the bloody deed, he would quote this passage of ScriptureHe that knoweth his
masters will,...