Jeremiah 51:36 - Matthew Poole's English Annotations on the Holy Bible

Men had need take heed how they give cause of appeals to God against them, especially the appeals of such as are a people that have a covenant relation to God. God in those cases ordinarily showeth himself a swift witness and judge, and gives a speedy judgment in such causes. Behold, saith God, I will plead thy cause, not with words, but actually with my judicial dispensations, therefore it is expounded by taking vengeance. The vengeance which God threateneth is expressed metaphorically under the notion of drying up her sea, and making her springs dry, which signifies the depriving her of all necessaries, not only of the abundance of her men, riches, treasures, but of her springs. Thus I had rather expound it, than as referring to the particular stratagem by which Cyrus took Babylon, viz, by drying up in some measure the river Euphrates, that is, turning it into other channels.