The mighty always keep their prey. The larger culture from which Nephi’s family departed allowed the keeping of captives. It was lawful to do so. Yet the query here suggests that order will change. The “mighty” and what is “lawful” does not overrule God. He is able to deliver, and none are mightier than He. Babylon, or the world’s corruptions, will not keep His chosen people from His liberating covenant. He will bring again Zion. And in Zion His people will leave their captivity, no longer being prey to the evils of the world.