Isaiah 20:3-4

Later the LORD explained, “In the same way that my servant Isaiah has walked around in undergarments and barefoot for the past three years, as an object lesson and omen pertaining to Egypt and Cush, so the king of Assyria will lead away the captives of Egypt and the exiles of Cush, both young and old. They will be in undergarments and barefoot, with the buttocks exposed; the Egyptians will be publicly humiliated.