And they ... put out the eyes of Zedekiah, and bound him with fetters of bronze, and carried him to Babylon. And in the fifth month, on the seventh day of the month, which is the nineteenth year of king Nebuchadnezzar king of Babylon, came Nebuzaradan, captain of the guard, a servant of the king of Babylon, to Jerusalem. And he burned the house of the Lord [the Temple], and the king's house, and all the houses of Jerusalem, and every great man's house burned he with fire. (2 Kings 25: 7-9)
With the destruction of the Temple -- on the 9th of Av of the year 422 BCE -- the special connection that the Jewish people had with God is severed.
Here is when it all comes crashing down. Besides the horrific physical destruction, there is also the great spiritual ego-deflation of the Jewish people.
Where previously the Babylonians had been satisfied in making Israel into a vassal state, this time their punishment is much worse. They decide to carry on the Assyrian policy of exile and remove the Jews from the Promised Land.
please feel free to comment and post additional resources that support this finding. I'm highly curious about this event.