Who is this that cometh up as a flood Here the king of Egypt is compared to a mighty river, the Nile, or the Euphrates, when it swells above its banks, and threatens to overwhelm the country with ruin and desolation. And he saith I will go up, and will cover the earth With my numerous armies; I will destroy the city Carchemish or Babylon; and the inhabitants thereof Who shall not be able to withstand the powerful force I bring against them. Thus the prophet represents him as beginning his march with all the ostentation and insolence of presumed success. Come up, ye horses; and rage, ye chariots, &c. Here he is exhibited calling aloud to the nations of which his army is composed, giving them the signal for action, and rousing them to deeds of desperate valour; but all in vain: for the time is come for God to avenge himself of his ancient foes: they are doomed to slaughter, to fall a bloody sacrifice on the plains of the north. For, adds the prophet, Jeremiah 46:10, this is the day of the Lord God of hosts That is, as it follows, the day of his vengeance. Hence, the day of the Lord is used in the New Testament to signify the day of judgment, of which all other days of vengeance are the earnests and forerunners. That he may avenge himself of his adversaries Of the idols of Egypt and their worshippers: the Egyptians were some of the first idolaters, and carried idolatry to its greatest height. And the sword shall devour, it shall be satiate, &c. These metaphorical expressions signify the very great slaughter which would be made at that time in the Egyptian army. For the Lord God hath a sacrifice, &c. The slaughter of men in battle, which is by way of punishment for their sins, is called a sacrifice to God, because it makes some kind of satisfaction and atonement to the divine justice. See the margin.
Jeremiah 46:7-10
7 Who is this that cometh up as a flood, whose waters are moved as the rivers?
8 Egypt riseth up like a flood, and his waters are moved like the rivers; and he saith, I will go up, and will cover the earth; I will destroy the city and the inhabitants thereof.
9 Come up, ye horses; and rage, ye chariots; and let the mighty men come forth; the Ethiopiansa and the Libyans, that handle the shield; and the Lydians, that handle and bend the bow.
10 For this is the day of the Lord GOD of hosts, a day of vengeance, that he may avenge him of his adversaries: and the sword shall devour, and it shall be satiate and made drunk with their blood: for the Lord GOD of hosts hath a sacrifice in the north country by the river Euphrates.