Iain Provan considers the content, and the nature, of law – as well as something greater.
Old Testament law does to some extent sanction particular kinds of slavery. But it also puts boundaries around all of that and tries to make sure it is much more humane than it otherwise might be. And we have to understand here that when something is sanctioned in the law, it doesn’t necessarily mean that it is absolutely right. It simply means that the purpose of law is not to try to bring in the kingdom of God by Wednesday, but in fact simply to limit the ability of evil to wreak havoc and so on.
So any legal system in fact would be very unwise to try to legislate virtue. Legal systems generally restrain themselves and limit themselves to doing some good to make sure things are not worse than they need be. So the real guide to what scripture thinks about slavery is actually the same image-bearing passages at the beginning of the story that we read about. And that’s what the early Christians understood, which is why they insisted on treating slaves as brothers and sisters in Christ and part of the fellowship and part of the community.