John Calvin Commentary Jeremiah 51:9

"We would have healed Babylon, but she is not healed: forsake her, and let us go every one into his own country; for her judgment reacheth unto heaven, and is lifted up even to the skies." — Jeremiah 51:9 (ASV)

The Prophet assumes different characters; he speaks here in the person of those who themselves brought help to the Babylonians. Many, no doubt, would have been ready to assist them if King Belshazzar had wished to accept aid; and we also know that the city had a large army. He then compares the nations subject to the Babylonians, and also the hired and foreign soldiers, to physicians, as if he had said, “Babylon has been healed with great care.”

As when a great prince is taken ill, he sends here and there for the best and most skillful physicians. But when the disease is incurable, they all strive in vain to save his life. So now the Prophet speaks, using a metaphor, but he speaks in the person of those who either had been hired or had come from a sense of duty to heal Babylon. “See,” they said, “the fault is not with us, for we have faithfully and carefully done our best to heal her, but she has not been healed.”

He then adds, Leave her, and let us depart, every one to his own land. This was the language of foreign soldiers and mercenaries. When they saw that the safety of the city was hopeless, they began to counsel one another, “What are we doing? Should we not rather consider our own safety? For our efforts are completely useless. It is then time for everyone to return to his own country, for the end of Babylon has come.”

But the change of person has much more force than if the Prophet had spoken in this way: “The time will come when the auxiliaries will flee away, for they will see that it would be completely in vain to defend her.” When he compares them to physicians, this comparison more fully illustrates the case; and then, when he speaks in their person, this renders what is said still more emphatic.

He finally adds, For her judgment has reached to the heavens, and has been elevated to the clouds. Jeremiah could not have properly addressed what he said to the unbelievers if you explain this as God being adverse and hostile to the Babylonians, because it never occurred to the hired soldiers that Babylon perished through the just judgment of God.

But the Prophet, according to a common way of speaking, says, Her judgment (that is, her destruction) reached to the heavens, and has been elevated to the clouds; that is, no aid will be found under heaven that can deliver Babylon. Why is this so? Because it will be the same as if destruction came from heaven itself and from the clouds. For when danger is near, either from behind or from before us, we can turn aside to the right hand or to the left, so that we may escape the evils that men may bring on us. But when heaven itself seems to threaten our heads, then an escape is attempted in vain. This, then, is the reason why the Prophet says that the judgment of Babylon had reached to the heavens and had been elevated to the clouds.