Isa Isaiah, chapter Book of Isaiah, chapter 20
A Sign against Egypt and Cush
Before the year that the chief commander, sent by Sargon king of Assyria, came to Ashdod and attacked and captured it, 2Ki 18:17the LORD had already spoken through Isaiah son of Amoz, saying, “Go, remove the sackcloth from your waist and the sandals from your feet.”
And Isaiah did so, walking around naked and barefoot.2Ki 1:8; Zec 13:4
Then the LORD said, “Just as My servant Isaiah has gone naked and barefoot for three years as a sign and omen against Egypt and Cush,20:3 That is, the upper Nile region; similarly in verses 4 and 5 so the king of Assyria will lead away the captives of Egypt and the exiles of Cush, young and old alike, naked and barefoot, with bared buttocks— to Egypt’s shame.
Those who made Cush their hope and Egypt their boast will be dismayed and ashamed. And on that day the dwellers of this coastland will say, ‘See what has happened to our source of hope, those to whom we fled for help and deliverance from the king of Assyria! How then can we escape?’”2Ki 17:4