Everyone in Jerusalem had promised to be loyal to Babylonia, and so none of them will believe that this could happen to them. But Babylonia's king will remind them of their sinful ways and warn them of their coming captivity.
Tell them that as surely as I am the living LORD God, I don't like to see wicked people die. I enjoy seeing them turn from their sins and live. So if the Israelites want to live, they must stop sinning and turn back to me.