doomer

Well, murder is a sin and they murdered this bystander here.

Taking your question at face value, there are actually multiple places in the Old Testament where kidnapping is forbidden, but sometimes it used a verb for "steal" that applies to both people and property and the common translations use "steal," which obviously usually only applies to property. afaik Jesus Himself never really comments on it because human trafficking was already understood to be against Jewish law, just like many other issues that he doesn't bother relitigating. That said, he tended to oppose violence even against "evil" figures, as when he broke up a fight and healed that Roman soldier's ear or whatever it was.

But my suggestion is to try to understand what their actual values are and argue from there. Inevitably it sounds like it mostly comes from (their selected points in) the Bible, but that doesn't mean that quoting scripture directly on an issue is the best or even really a good way of persuading them. At base, it's unavoidable that they personally believe in things, and identifying those things is the best way to persuade them because something that doesn't properly interact with those things will simply be brushed off.