And the LORD said, Like as my servant Isaiah hath walked naked and barefoot three years for a sign and wonder upon Egypt and upon Ethiopia;

Wesley's Notes

20:3 Three years - Not constantly, but when he went abroad among the people, to whom this was appointed for a sign. A sign - When this judgment should come, namely, three years after this prophecy.

Jamieson-Fausset-Brown Bible Commentary

3. three years-Isaiah's symbolical action did not continue all this time, but at intervals, to keep it before the people's mind during that period [Rosenmuller]. Rather, join "three years" with "sign," a three years' sign, that is, a sign that a three years' calamity would come on Egypt and Ethiopia [Barnes], (Isa 8:18). This is the only instance of a strictly symbolical act performed by Isaiah. With later prophets, as Jeremiah and Ezekiel, such acts were common. In some cases they were performed, not literally, but only in prophetic vision.

wonder-rather, "omen"; conveying a threat as to the future [G. V. Smith].

upon-in reference to, against.

Matthew Henry's Concise Commentary

20:1-6 The invasion and conquest of Egypt and Ethiopia. - Isaiah was a sign to the people by his unusual dress, when he walked abroad. He commonly wore sackcloth as a prophet, to show himself mortified to the world. He was to loose this from his loins; to wear no upper garments, and to go barefooted. This sign was to signify, that the Egyptians and Ethiopians should be led away captives by the king of Assyria, thus stripped. The world will often deem believers foolish, when singular in obedience to God. But the Lord will support his servants under the most trying effects of their obedience; and what they are called upon to suffer for his sake, commonly is light, compared with what numbers groan under from year to year from sin. Those who make any creature their expectation and glory, and so put it in the place of God, will, sooner or later, be ashamed of it. But disappointment in creature-confidences, instead of driving us to despair, should drive us to God, and our expectation shall not be in vain. The same lesson is in force now; and where shall we look for aid in the hour of necessity, but to the Lord our Righteousness, throne of grace, and serving with each other in the same business of religion, should end all disputes, and unite the hearts of believers to each other in holy love.