“”I cannot help thinking, that some of those servants mentioned by the Apostles in their epistles, were or had been slaves. It is plain, that the Gibeonites were doomed to perpetual slavery, and though liberty is a sweet thing to such as are born free, yet to those who never knew the sweets of it, slavery perhaps may not be so irksome.
|—George Whitefield, Works, volume 2, letter DCCCLXXXVII|
George Whitefield was the most famous preacher of the First Great Awakening, a founder of Methodism, and an advocate for slavery (to make his plantation profitable), leading to the successful introduction of slavery to Georgia which isn't it ironic given that the founder of methodism hated slavery. Rubbing salt into the wound, he is also remembered as one of the first to preach to slaves.
Along with Jonathon Edwards, Whitefield heavily influenced American Christianity by popularizing a style of preaching that sought to elicit an emotional response from the audience. Whitefield and other preachers in the First Great Awakening introduced techniques like the "mourner's bench" (the predecessor to the alter call) to draw audience members to the front of the church to convert or rededicate themselves to God.
Despite preaching Calvinism and lobbying for slavery, he arguably did do some good things; the Bethesda Orphanage he created is the oldest charity in the US (although even that was tainted; built from the proceeds of slavery and maintained in part by slaves).