In the fourth year — This circumstance lets us know that this prophecy was many years before Babylon was destroyed; for it was seven years before Jerusalem was taken; so as it must be above sixty years before it was fulfilled in the first degree.
Related Commentaries of Jeremiah 51:59
Jeremiah 51:59
59 The word which Jeremiah the prophet commanded Seraiah the son of Neriah, the son of Maaseiah, when he went with Zedekiah the king of Judah into Babylon in the fourth year of his reign. And this Seraiah was a quiet prince.