Jeremiah 51:64 - Matthew Poole's English Annotations on the Holy Bible

It hath been often said that Euphrates was that great river which ran by the walls of Babylon; into this Seraiah is commanded by Jeremiah to throw this roll of prophecy against Babylon, symbolically to teach the Jews, that according to the tenor of his prophecy the time should come, after some years, when Babylon should be destroyed never to rise again to any great view or degree of splendour, no more than that roll with the stone tied to it should rise from the bottom of Euphrates. And they shall be weary; some read, though they weary themselves, that is, do what they can, or, (as it is here,) and they shall be weary with that weight of judgment which shall be upon them. Thus far are the words of Jeremiah: either the words of Jeremiah relating to Babylon reach thus far, or all the words of Jeremiah remaining on sacred record (for it is thought that the next chapter was rather penned by some other holy man); or (which seemeth the best) the prophetical words of Jeremiah, for the matter of the next chapter is historical, and the Book of Lamentations is not prophetical, as to the main of it, though there be in it three or four prophetical passages, Lamentations 4:21,22, &c.