The prophet Jeremiah was told by the Lord to buy a loincloth, go the the Euphrates, and hide it in a cleft of the rock. Later he was told to retrieve it and use it as a visual aid to the tribe of Judah of how they have been spoiled.
Jeremiah wrote a book of all the disaster that would come upon Babylon and read it to Seraiah when he went edekiah king of Judah to Babylon. After reading the book to him, Jeremiah tied it to stone and threw it into the Euphrates and said, "Thus shall Babylon sink, to rise no more."
In the apocalyptic book of Revelation the sixth trumpet angel is commanded to "release the four angels who are bound at the great river Euphrates." Also in Revelation the sixth bowl angel poured out his bowl on the great river Euphrates drying up the water to prepare the way for the kings of the east to march to Armageddon.