And so, look now, the Lord is bringing upon them the waters of the River, mighty and numerous, (namely), the king of Assyria and all his glory, and he shall run over all his courses, and go over all his banks. And he will push on against Judah, overflow and sweep over, reaching even the neck. And his outspread wings will fill the breadth of your land, 0 Immanuel. (8:7-8)
The Assyrians often compared their military prowess to the waters of the Flood (abubu). This was not just any flood, but the waters of the Great Flood that destroyed the earth. Isaiah picks up on this metaphor in Isaiah 8:6-8. Because the people refused the gentle brook of Shiloah, the LORD was bringing on them the waters of ‘the River’, a reference to the Euphrates.
There is an interesting relief in the British Museum that actually shows Assyrian soldiers swimming across the Euphrates River on inflated animal bladders. Horses swim next to them while the chariots have been dissembled and are being carried across the river in little coracles. It is a striking depiction of the words of Isaiah.
As is so typical in Isaiah, the foretelling of doom is followed by words of hope – in this case, the promise of Emmanuel. Although the water would reach up to the neck – ultimately, those who fight against the LORD will be destroyed “for God is with us”.
Be broken, you peoples, and be shattered; give ear, all you far countries; strap on your armor and be shattered; strap on your armor and be shattered. Take counsel together, but it will come to nothing; speak a word, but it will not stand, for God is with us. (Isa 8:9,10 ESV)