Jeremiah 51:63 in the World English Bible
It will be, when you have finished reading this book, that you shall bind a stone to it, and cast it into the middle of the Euphrates.
Context
62 Then shalt thou say, O LORD, thou hast spoken against this place, to cut it off, that none shall remain in it, neither man nor beast, but that it shall be desolate for ever.
63 And it shall be, when thou hast made an end of reading this book, that thou shalt bind a stone to it, and cast it into the midst of Euphrates:
64 And thou shalt say, Thus shall Babylon sink, and shall not rise from the evil that I will bring upon her: and they shall be weary. Thus far are the words of Jeremiah.