Isaiah 20:2-4

at that time Jehovah spake by Isaiah the son of Amoz, saying, Go, and loose the sackcloth from off thy loins, and put thy shoe from off thy foot. And he did so, walking naked and barefoot. And Jehovah said, Like as my servant Isaiah hath walked naked and barefoot three years for a sign and a wonder concerning Egypt and concerning Ethiopia; so shall the king of Assyria lead away the captives of Egypt, and the exiles of Ethiopia, young and old, naked and barefoot, and with buttocks uncovered, to the shame of Egypt.