For three years, the people could see Isaiah going about in this way and wonder about what it could mean. The reason for Isaiah’s humiliation is given in this verse. Isaiah uses the Lord’s words to explain that his symbolic actions were a sign of what would happen when Egypt and Cush fell.
3 Et l'Eternel dit: De même que mon serviteur Esaïe marche nu et déchaussé, ce qui sera dans trois ans un signe et un présage pour l'Egypte et pour l'Ethiopie,