Isaiah 20:2 - Joseph Benson’s Commentary on the Old and New Testaments

Go loose the sackcloth from off thy loins 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. And he did so, walking naked and barefoot 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. Vitringa.