“Thus says the Lord Yahweh, They also who uphold Egypt will fall, and the pride of her power will come down, from Migdol to Seveneh will they fall in it by the sword, says the Lord Yahweh. And they will be desolate in the midst of the countries that are desolate, and her cities will be in the midst of the cities which are wasted. And they will know that I am Yahweh, when I have set a fire in Egypt, and all her helpers are destroyed. In that day will messengers go forth from before me in ships to make the careless Cush afraid, and there will be anguish on them as in the day of Egypt. For lo, it comes.”
The message of gloom for Egypt continues. Their allies will also fall, and the ‘pride of their power' (their powerful leadership or cities?) will come down, from northern border to southern border, smitten by the sword. All at the word of the Lord Yahweh. And their desolation will be shared by countries round about. It will be as though a fire has been lit in Egypt which will consume them and their allies. And when this happens all will know by experience that He is Yahweh, the One Who is what He wants to be.
Then Yahweh's messengers (possibly referring to the Babylonians?) will go by ship up the Nile to Cush who thought they were safe, and they too will suffer anguish. These may be Yahweh's messengers simply because they carry news of what Yahweh has done, or in the sense that troops are shipped with a ‘message' of action and destruction.
We do not have external information on how far Nebuchadnezzar went in his invasion before, in the end, he accepted peace terms. But Egypt would not have surrendered easily.
‘Lo, it comes.' What was to happen was inevitable. Nothing would prevent it.