Answer: His master is crueler after finding religion than he was before.
Explanation:
Douglas considered his master as a cruel man. His master once went out for a christian camp meeting and in the course of the meeting, he surrendered his life to Christ. Due to this, Douglass hoped that this religious transformation would result in his master being less cruel toward his slaves, and this didn't turn out to be the case, rather the master became more cruel.
This is an irony, because Douglass experienced the opposite of his expectation. An irony is the expression of one's meaning by the use of language which normally signifies the opposite, usually for emphatic or humorous effect.