In a recent post, I quoted historian Rodney Stark extensively about how religions are not all the same. The different theologies of god in the world religions produce very different kinds of moral systems—some religions have no moral features at all. Consequently, monotheism, and Christianity in particular, was uniquely capable of theologies of God and humanity that made slavery incompatible with faithfulness. It was only when the Bible was corrupted by unchristian motivations that it was perverted to excuse an evil and sinful institution. From the beginning of the church, Christianity developed theology that condemned slavery. The church in the American South and other Christians throughout history who used the Bible to justify their bigotry and enslavement of human beings were the tragic exceptions to the rule. Their abuse of the Bible stood against the broad and historical understanding of what Christians believed the Bible taught about the equality and intrinsic value of every human being, not matter their race.
Some excerpts from Rodney Stark’s book For the Glory of God: How Monotheism Led to Reformations, Science, Witch-Hunts, and the End of Slavery:
Antislavery doctrines began to appear in Christian theology soon after the decline of Rome and were accompanied by the eventual disappearance of slavery in all but the fringes of Christian Europe. When Europeans subsequently instituted slavery in the New World, they did so over strenuous papal opposition, a fact that was conveniently “lost” from history until recently...
Except for several early Jewish sects, Christian theology was unique in eventually developing an abolitionist perspective...
As early as the seventh century, Saint Bathilde (wife of King Clovis II) became famous for her campaign to stop slave-trading and free all slaves; in 851 Saint Anskar began his efforts to halt the Viking slave trade. That the Church willingly baptized slaves was claimed as proof that they had souls, and soon both kings and bishops—including William the Conqueror (1027-1087) and Saints Wulfstan (1009-1095) and Anselm (1033-1109)—forbade the enslavement of Christians. Since, except for small settlements of Jews, and the Vikings in the north, everyone was at least nominally a Christian, that effectively abolished slavery in medieval Europe...
The first shipload of black slaves [arrived in Portugal in the 15th century], and as black slaves began to appear farther north in Europe, a debate erupted as to the morality and legality of slavery. A consensus quickly developed that slavery was both sinful and illegal.... The principle of “free soil” spread: that slaves who entered a free country were automatically free. That principle was firmly in place in France, Holland, and Belgium by the end of the seventeenth century. Nearly a century later, in 1761, the Portuguese enacted a similar law, and an English judge applied the principle to Britain in 1772. Although exceptions involving a single slave servant or two, especially when accompanying a foreign traveler, were sometimes overlooked, “beyond a scattering of servants in Spain and Portugal, there were very few true slaves left in Western Europe by the end of the sixteenth century”...
The problem wasn’t that the Church failed to condemn slavery; it was that few heard and most of them did not listen...
In 1787 the Quaker-inspired Pennsylvania Society for Promoting the Abolition of Slavery was headed by Benjamin Franklin and Benjamin Rush, two of the most respected and influential living Americans. Not to be outdone, many Christian groups and luminaries took up the cause of abolition, and soon abolitionist societies sprang up that were not associated with a specific denomination. But, through it all, the movement (as distinct from those it made sympathetic to the cause) was staffed by devout Christian activists, the majority of them clergy. Indeed, the most prominent clergy of the nineteenth century took leading roles in the abolition movement...
Moreover, as abolition sentiments spread, it was primarily the churches (often local congregations), not secular clubs and organizations, that issued formal statements on behalf of ending slavery. The outspoken abolitionism expressed by Northern congregations and denominational gatherings caused major schisms within leading Protestant denominations, eventuating in their separation into independent Northern and Southern organizations...
[A] virtual Who’s Who of “Enlightenment” figures fully accepted slavery.... It was not philosophers or secular intellectuals who assembled the moral indictment of slavery, but the very people they held in such contempt: men and women having intense Christian faith, who opposed slavery because it was a sin.