The prophet, Jeremiah reminded Zedekiah of the dominion that Babylon would have over Judah. He, along with his people would be given into their hands. Jerusalem would burn and he would die in Babylon, but would die in peace and be mourned properly.
One of the provisions of the law of Moses was the release of slaves in the seventh year. That commandment had been ignored for many years. As an attempt to regain favor with God, the Judeans released all of their slaves in compliance with that command. However, that did not last long. Everyone went out and reclaimed their slaves. With the breaking of that covenant, all avenues of salvation from Babylon were closed. Destruction was imminent.