Frederick Douglass wrote in “What to the Slave is the Fourth of July?” (which can be found in A House Divided: The Antebellum Slavery Debates in America, 1776-1865):
The church of this country is not only indifferent to the wrongs of the slave, it actually takes sides with the oppressors. It has made itself the bulwark of American slavery, and the shield of American slave-hunters. Many of its eloquent Divines, who stand at the very lights of the church, have shamelessly given the sanction of religion and the Bible to the whole slave system. They have taught that man may, properly be a slave; that the relation of master and slave is ordained of God; that to send back an escaped bondman to his master is clearly the duty of all the followers of the Lord Jesus Christ; and this horrible blasphemy is palmed off upon the world for Christianity. For my part, I would say, welcome infidelity! Welcome atheism! Welcome anything! in preference to the gospel, as preached by these Divines! They convert the very name of religion into an engine of tyranny and barbarous cruelty, and serve to confirm more infidels, in this age, than all the infidel writings of Thomas Paine, Voltaire, and Bolingbroke put together have done! We are met on the threshold of our efforts for the redemption of the slave, by the church and ministry of the country, in battle arrayed against us; and we are compelled to fight or flee. From what quarter, I beg to know, has proceeded a fire so deadly upon our ranks, during the last two years, as from the Northern pulpit? As the champions of the oppressors, the chosen men of American theology have appeared men honored for their so-called piety, and their real learning…. My spirit wearies of such blasphemy; and how such men can be supported, as the standing types and representatives of Jesus Christ is a mystery which I leave others to penetrate…
Fellow-citizens! I will not enlarge further on your national inconsistencies. The existence of slavery in this country brands your republicanism as a sham, your humanity as a pretense, and your Christianity as a lie. It destroys your moral power abroad; it corrupts your politicians at home. It saps the foundation of religion; it makes your name a hissing, and a byword to a mocking earth.