John Wesley on Jeremiah 51:32

The passages - The passages over the river Euphrates, and all the other passages by which the Babylonians might make their escape, were guarded with soldiers. Reeds - On the border of the river Euphrates were vast quantities of great and tall reeds, which with the mud in which they stood, were as another wall to the city; but the Medes had burnt them so as the way was open.