John Calvin Commentary Jeremiah 46:7-8

"Who is this that riseth up like the Nile, whose waters toss themselves like the rivers? Egypt riseth up like the Nile, and his waters toss themselves like the rivers: and he saith, I will rise up, I will cover the earth; I will destroy cities and the inhabitants thereof." — Jeremiah 46:7-8 (ASV)

The Prophet again addresses those doubts that might have possessed the minds of the godly, preventing them from receiving this prophecy in faith and with due reverence. For we have said that when our thoughts are occupied with external things, God's power is disregarded. Therefore, when we speak of some impregnable kingdom, it does not occur to us that all strongholds are of no account to God.

It was therefore necessary to highly extol God's power when the Prophets spoke of His judgments. Otherwise, the flesh, as we have stated, would have said, “Those who are well fortified must be free from evils and, as it were, beyond the reach of weapons; and therefore, there is nothing for them to fear.” And it is with this false imagination that the proud deceive themselves, for they set up their forces, their auxiliaries, and all the things they deem, according to the judgment of the flesh, as sufficient to protect their safety. Thus it happens that they heedlessly disregard all threats, because they think that the resources they have are so many fortresses against all attacks.

It is for this purpose that the Prophet now says, Who is this that as a lake rises, or swells, as rivers are moved, or, whose waters are agitated? But he speaks according to the common judgment of men, for the very sight could not help but fill men with fear; and so the Jews could never have thought possible what the Prophet here asserts.

He then, as it were, introduces them all as anxiously inquiring according to their own judgment, Who is this? as though Pharaoh were not a mortal, but something above human. For the gist of the question is this: that Pharaoh was, as it were, exempted from the common condition of men because his power increased like a river rising or swelling; and its waters, he says, make a noise.

Then he adds, Egypt is like rivers and like a lake: it made a noise with its forces, as though a river were rolling along its waters. But all this would be nothing, as he afterwards tells us; he adds, he hath said, I will ascend, I will cover the land, I will destroy the city, etc.

He puts city in the singular instead of the plural number; I will destroy cities, he says, and all who dwell in them. In short, he sets forth Pharaoh here as one who triumphed before he fought, because he could cover the land with the multitude of his footmen and horsemen.