Jeremiah 51:46

But there is a doctrine here especially useful; for when God designs to aid his Church, he suffers the world to be, in a manner, thrown into confusion, that the favor of redemption may appear more remarkable. Unless, then, the faithful were to have some knowledge of God’s mercy, they could never endure with courageous minds the trials by which God proves them, and while Satan, on the other hand, seeks to upset their faith. There is the prelude of this very thing to be seen in the ancient people: God had promised to be their redeemer; when the day drew nigh, war suddenly arose, and the Medes and the Persians, as locusts, covered the whole land. We know what various evils war brings with it. There is, then, no doubt but that the children of God sustained many and grievous troubles, especially as they were exiles there; they must have suffered want, they must have been harassed in various ways. Now, as the event of war was uncertain, they might have fainted a hundred times, had they not been supported by this prophecy. But, as I have said, so now also God deals with his Church; for when a deliverer appears, all things seem to threaten ruin rather than to promise a joyful and happy deliverance. It is then necessary, that these prophecies should come to our minds, and that we should apply, for our own benefit, what happened formerly to our fathers, for we are the same body. There is, therefore, no reason for us at this day to wonder, if all things seem to get worse and worse, when yet God has promised that the salvation of his Church will ever be precious to him, and that he will take care of her: how so? because it is said, Let not your heart be faint, fear ye not when rumors arise, one after another; when one year brings tumults, and then another year brings new tumults, yet let not all this disturb your minds.

And Christ seems to allude to these words of the Prophet, when he says,

“Wars shall arise, and rumors of wars: be ye not troubled.” (Matthew 24:6)

These words of Christ sufficiently warn us not to think it strange, if the Church at this day be exposed to violent waves, and be tossed as by continual storms: why so? because it is right and just that our condition should be like that of the fathers, or at least approach to it. We now, then, understand the design of the Prophet, and the perpetual use that ought to be made of what is here taught.

He afterwards adds, Violence in the land, and a ruler upon or after a ruler. This refers to Cyrus, who succeeded Darius, whom some call Cyaxares. They, indeed, as it is well known, both ruled; but Darius, who was older, had the honor of being the supreme king. Afterwards Cyrus, when Darius was dead, became the king of the whole monarchy. And Darius the Mede lived only one year after Babylon was taken. But I doubt not but that the Prophet here bids the Jews to be of good courage and of a cheerful mind, though the land should often change its masters; for that change, however often, could take away nothing from God’s authority and government. It afterwards follows, —