And Nebuchadnezzar king of Babylon came to the city while his servants were besieging it, and Jehoiachin the king of Judah gave himself up to the king of Babylon, himself and his mother and his servants and his officials and his palace officials. The king of Babylon took him prisoner in the eighth year of his reign...
2 Kings 24:11-12
This is the beginning of the end for Judah. The king is taken away to Babylon. Nebuchadnezzar installs a puppet king, Zedekiah, on the throne and the first wave of the exile of the Jews begins with the Babylonians leading away captive all the high ranking officials, people of wealth and influence, and military class of Judah. The land is left with just the poorest of Jewish peasants living in it under Babylonian administration.
The text is clear that this circumstance was not a chance takeover by a random power. God had promised judgment and had foretold a captivity for His people, right down to a description of what valuable national treasures would be ransacked (2 Kings 24:13). The outworking of this came with Nebuchadnezzar's armies. The Babylonians were the means of God's justice. The exile was the curse of the Law enacted upon the disobedience of the people of Judah. Their failure to keep the covenant led to their present horror and pain.
We see the sovereignty of God at work. It was His plan, even in this wartime siege and occupation of Jerusalem, to remind the survivors of His power and His covenant with them. And although the reminder was harsh, it eventually would be effective. Never again would the Jews post exile commit outright visible idolatry as a nation. The captivity would change the spiritual direction of God's people. And it started with the loss of a kingdom. Once they were no longer in control, they could begin to acknowledge God's control over them.