Adam Clarke on Jeremiah 25:11

Shall serve the king of Babylon seventy years - As this prophecy was delivered in the fourth year of Jehoiakim, and in the first of Nebuchadnezzar, and began to be accomplished in the same year, (for then Nebuchadnezzar invaded Judea, and took Jerusalem), seventy years from this time will reach down to the first year of Cyrus, when he made his proclamation for the restoration of the Jews, and the rebuilding of Jerusalem. See the note on Isa 13:19 (note), where the subject is farther considered in relation to the reign of Nebuchadnezzar, and the city of Babylon.