My bread and butter course at Baylor University is the "America to 1877" survey class. The most troubling issue I cover in the class is slavery. What especially piques the interest of Christian students is the biblical case against slavery - or the lack thereof.

"How do we know the Bible is against slavery?" I ask. Most students have never given much thought to the issue. Of COURSE the Bible is against slavery, they assume, because slavery is wrong. "OK, give me some verses that tell us that slavery is wrong," I say. Silence. Some savvy students might cite the Golden Rule of Luke 6:31.

Occasionally someone remembers Galatians 3:28, and its note that in Christ there is neither slave nor free - although that does not quite tell us that slavery is wrong. Just because in Christ there is neither male nor female, slave nor free, Jew nor Greek, does not mean that those identities cease to exist.

What does the Bible say about slaves and masters, I ask them? Again, some remember the household codes of Ephesians and Colossians, where servants/slaves are told to obey their masters. Or they note various other Old and New Testament practices where the authors seem to assume the existence of slavery, rather than commenting on its morality.

It is hard to imagine a more challenging historical and scriptural topic than slavery. It has become ammunition used by skeptics who have denounced the Bible as fundamentally immoral. I believe that maturing Christians should grapple with these kinds of Bible "problems," instead of just assuming that the Scriptures give us transparent answers to all of life and history's conundrums.

Moreover, we can in fact make a powerful argument for how the Bible undercuts slavery, as it was typically practiced. But the argument requires more work, and more historical understanding, than the simplistic notion that the Bible is "against slavery."

Usually, when we think about the practice of slavery, we think of slaves working on a plantation. Fair enough. In antebellum America, slaves found themselves working in a variety of jobs, but agricultural labor was the most common. And when you focus on this kind of "slavery in the abstract," you have a tougher time making a Christian case that it was absolutely wrong.

Was physical and sexual abuse of slaves pervasive on the plantations? Absolutely. But proslavery writers readily admitted that those practices were wrong. Christian masters could fulfill their responsibilities to slaves and still, in good conscience, remain masters, the proslavery advocates argued.

But even "good" Christian masters, those who did not abuse their slaves, still participated in the broader "system" of slavery. And this is where the strongest arguments against slavery come in. In the modern system of transatlantic slavery, from roughly 1500 to its American demise in the Civil War, there were two related, and fundamentally immoral, phases to the slave trade. One was the massive system of slave capturing in Africa. The other, more narrowly focused in the United States, was the massive system of domestic slave trading in the antebellum era. Both of these depended on treating slaves as "chattel," or property, which entailed a variety of sins. The actual practices of chattel slavery denied the slaves their basic dignity, as humans made in the image of God.

To understand why slavery was, at root, immoral, we may need to shift our mental image of the paradigmatic slave experience. Instead of a slave picking cotton, perhaps we should shift our image to the European or African slave trader snatching away a child in the African interior. Or a husband, wife, or child being examined for sale in the New Orleans slave market.

Slaves who spoke on the matter, like the African American pastor James W.C. Pennington, who had run away from his master in his teens, knew that the "chattel principle" of slavery was at the dark heart of the institution. Pennington wrote that the "being of slavery, its soul and its body, lives and moves in the chattel principle, the property principle, the bill of sale principle: the cart-whip, starvation, and nakedness are its inevitable consequences."

When the slave trade became a truly massive undertaking in the 1700s, many Africans were stolen into slavery. And this brings into play perhaps the most overt anti-slavery verse in the Bible, I Timothy 1:10, which classes "menstealers" as gross sinners along with murderers and "whoremongers" (KJV). Most have understood menstealers to be slave traders, especially those who steal people away to sell them as slaves. Some early modern slaves in the Americas were taken as war captives, too, but large numbers were simply captured and taken away from their families. That sin, repeated thousands of times over, fatally corrupted slavery in the Americas.

The United States closed its transatlantic commerce in slaves in 1808, shifting the focus to the domestic sale and transfer of slaves. Outright kidnapping was less common in this system, but every slave owner was associated with a system that, at a moment's notice, could rip a slave away from husband or wife, parent or child, community and church. Countless churches in the antebellum period had to discuss what to do with a slave who had been sold away from a spouse back east, and now wished to remarry.

These were not just heart-rending anecdotes of family separation, either, but an everyday threat. Historians estimate that perhaps one in three young slave children were separated from a parent, and one in three eastern slave marriages were broken up by the sale of a spouse to an owner further west in America, in places from Georgia to Texas.

We could also mention the corrupt racialized nature of American slavery, the dangerous power slavery gave to one human being over another, and its perpetual nature versus the "jubilee" system prescribed for ancient Israel. But on top of the systemic abuses perpetuated against slaves on the plantations, the slave system in America from the 1600s to the 1800s was built on a sinful foundation of manstealing. The chattel principle not only made a mockery of the slaves' human dignity, but it undermined the slaves' own obligations to their families. Were there masters who treated individual slaves "kindly"? Sure there were. But the slave system on which they depended for their livelihood was immoral, and unbiblical, at its core.