Slave trade

There is no biblical command to buy or sell slaves. Let's consider the question of whether it's intrinsically wrong to buy slaves.

Suppose there's a slave market. If you could, you'd abolish the slave market. But that's not within your power. At least, not in the short-term. 

So how do you respond to the status quo? Since slaves are going to be sold anyway, to someone or another, is it intrinsically wrong for you to buy slaves? 

Now, someone might object to the principle that if it's going to happen anyway, there's nothing wrong with me doing it too. And I agree that, as a general principle, that's morally unreliable. 

Notice, though, the question at issue is not: since other people are selling slaves, I might as well sell them. Rather, the question at issue is: since other people will buy slaves no matter what I do or don't do in that respect, are there circumstances under which it would be permissible, or even commendable, for me to buy them?

Our intuitive reaction typically depends on what examples spring to mind. From what I've read, there are millions of street kids around the world. It wouldn't surprise me if some street kids are sold into child prostitution, or even child sacrifice. For instance:

In Brazil we lived and worked in the Spiritist capital of the world [Sao Luis, Maranhao] where the sacrifice of children and the black market dealing of their body parts is still a common practice.  

http://20schemes.com/2013/should-we-let-them-live-thinking-about-halloween-in-the-schemes/

It's possible that's an urban legend. However, it may not be coincidental that, from what I've read, Brazil has huge numbers of street kids. So it might well be easy to procure a street kid for child sacrifice. Tragically, there's ready supply of unwanted, untended kids. 

If you were a wealthy Christian, would it be wrong for you to buy as many as you could afford–to rescue them from child prostitution, sweatshop labor, or child sacrifice? Presumably, that would be the right thing to do. So the answer depends, in part, on the motivation. 

However, a further objection might be what you buy them for. Are you buying their freedom? Or do they become your slaves instead of someone else's slaves? In my example, the wealthy Christian wouldn't buy them to enslave them. 

There is, however, another twist. In the past, masters were sometimes forbidden by law from freeing their slaves. In that situation, a master can't emancipate his slaves even if he wants to. 

I suppose one alternative would be to treat them like freemen, like hired hands, even if they were still technically enslaved. In a fallen world, we have to be ingenious.