The Prophet again meets those doubts which might have possessed the minds of the godly, so as to prevent them to receive this prophecy in faith and with due reverence: for we have said, that when our thoughts are occupied with external things, the power of God is disregarded. When, therefore, we speak of some impregnable kingdom, it does not come into our minds, that all strongholds are of no account with God. It was therefore necessary highly to extol the power of God, when the Prophets spoke of his judgments: otherwise the flesh, as we have stated, would have said, "They who are well fortified must be free from evils, and as it were beyond the reach of weapons, and hence 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 which they deem, according to the judgment of the flesh, as sufficient to protect their safety. Titus it happens, that they heedlessly disregard all threatenings, even because they think that the subsidies which 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 but fill men with fear; and so the Jews could never have thought that possible which 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 was not a mortal, but something above human. For the drift 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; [1] I will destroy cities, he says, and all who dwell in them. He in short 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. It now follows, --

Footnotes

1 - The city here is put in opposition to the land, -- And it (Egypt) said, I will ascend, I will cover the land; I will destroy (every) city, and the dwellers in it.

In Jeremiah 46:3-6 we saw only a mighty army marshalling for battle, and its hasty flight. In Jeremiah 46:7-12 the prophet tells us at whose defeat we have been present.
A flood - the Nile. The metaphor describing the advance of the Egyptian army is naturally drawn from the annual overflow of their own sacred stream.
Whose waters are moved - literally, his waters toss to and fro as the rivers, the natural branches of the Nile in Lower Egypt.

Who is this that cometh up as a flood - The vast concourse of people is here represented as a river: for instance, the Jordan, suddenly swollen with the rains in harvest, rolling its waters along, and overflowing the whole country. A fine image to represent the incursions of vast armies carrying all before them. Such was the army of Pharaoh-necho in its march to Carchemish.

Who [is] this [that] cometh up as (f) a flood, whose waters are moved as the rivers?
(f) He derides the boastings of the Egyptians, who thought by their riches and power to have overcome all the world, alluding to the Nile river, which at certain times overflows the country of Egypt.

Who is this that cometh up as a flood,.... These are either the words of the prophet, who having a vision in prophecy of the march of the Egyptian army from the south to the north, which he compares to a flood; in allusion to the river Nile, which used to overflow its banks, and spread itself over the land; because of the vast numbers of which it consisted; because of the noise it made, and, because of its rapidity and force, threatening to bear all down before it; as wondering, asks, who it was, whose army it was, and to whom it belonged? or they are the words of God, who puts this question, in order to, give an answer to it, and thereby upbraid the Egyptians with their arrogance, pride, and vanity; which would all come to nothing:
whose waters are moved as the rivers? whose numerous armies came with a great noise and force, like the openings of the Nile, the seven gates of it; which were very boisterous, especially in hard gales of wind: it is no unusual thing for large armies to be compared to floods and rivers, which move forcibly and swiftly, and make a large spread; see Isaiah 8:7. The Targum is,
"who is this that comes up with his army as a cloud, and covers the earth, and as a fountain of water, whose waters are moved?''

as a flood-- (Jeremiah 47:2; Isaiah 8:7-8; Daniel 11:22). The figure is appropriate in addressing Egyptians, as the Nile, their great river, yearly overspreads their lands with a turbid, muddy flood. So their army, swelling with arrogance, shall overspread the region south of Euphrates; but it, like the Nile, shall retreat as fast as it advanced.