In Isaiah, chapter twenty, verse two, “At the same time spake the LORD by Isaiah the son of Amoz, saying, Go and loose the sackcloth from off thy loins, and put off thy shoe from thy foot. And he did so, walking naked and barefoot.” In the Old Testament, Isaiah was to appear in public stripped of his outer clothes for three years as an enacted parable or sign of what would happen to Egypt and Cush when Assyria carried them into captivity. The message was intended to warn Judah not to trust in an alliance with Egypt, in those days, but rather to look to the Lord their God. Isaiah may not have been completely naked, but rather stripped to a loincloth; perhaps he conducted himself in this humiliating manner only a portion of each day.
The term “walking naked and barefoot,” in the Old Testament, means “uncovered himself.” For example, in Second Samuel six, verse twenty, David laid aside his royal clothing and appeared in a simple tunic, such as the servants wore, which is a person who serves often under duress. By the sackcloth is meant either the hairy garment usually worn by the prophets, or a mournful habit, such as was commonly made of sackcloth, which he wore in token of his grief for the great calamities that were already come upon Israel, and were coming on Judah. Not wholly naked, but without his upper garment; as slaves and prisoners used to do, whose condition he was to represent. This action was both agreeable to the mode of instruction made use of in those times, and, as it was intended to excite the attention of the Israelites, was likewise very well adapted to promote that intention.
The demonstration from Isaiah was the fulfillment of God’s commandment.