Yirmeyah 51:63

63 And it shall be, when thou hast made an end of reading this sefer, that thou shalt bind an even (stone) to it, and cast it into the midst of Euphrates;

Yirmeyah 51:63 Meaning and Commentary

Jeremiah 51:63

And it shall be, when thou hast made an end of reading this
book
To the captive Jews; and having also said the above words by way of prayer and approbation: [that] thou shalt bind a stone to it, and cast it into the midst of
Euphrates;
a river by which Babylon was situated. The book, being read, was to be rolled up again, and then a stone tied to it, and cast into the middle of the river, where the waters were deepest, and from whence it could not be taken up; and this was a sign confirming the above prophecy; compare with this what was done by a mighty angel concerning mystical Babylon, in which there is an allusion to this, ( Revelation 18:21 ) .

Yirmeyah 51:63 In-Context

61 And Yirmeyah said to Serayah, When thou comest to Bavel, and shalt see, and shalt read all these Devarim;

62 Then shalt thou say, Hashem, Thou hast spoken against this makom, to cut it off, that none shall remain in it, neither adam nor behemah, but that it shall be desolate forever.

63 And it shall be, when thou hast made an end of reading this sefer, that thou shalt bind an even (stone) to it, and cast it into the midst of Euphrates;

64 And thou shalt say, Thus shall Bavel sink, and shall rise no more because of the ra’ah that I will bring upon her. Thus far are the Devarim of Yirmeyah.