Adam Clarke on Isaiah 30:13

Swelling out to a high wall "A swelling in a high wall" - It has been observed before, that the buildings of Asia generally consist of little better than what we call mud walls. "All the houses at Ispahan, "says Thevenot, Vol. II., p. 159, "are built of bricks made of clay and straw, and dried in the sun; and covered with a plaster made of a fine white stone. In other places in Persia the houses are built with nothing else but such bricks, made with tempered clay and chopped straw, well mingled together, and dried in the sun, and then used: but the least rain dissolves them. "Sir John Chardin's MS. remark on this place of Isaiah is very apposite: Murs en Asie etant faits de terre se fendent ainsi par milieu et de haut en bas. "The walls in Asia being made of earth often cleave from top to bottom." This shouts clearly how obvious and expressive the image is. The psalmist has in the same manner made use of it, to express sudden and utter destruction: - "Ye shall be slain all of you;

Ye shall be like an inclining wall, like a shattered fence." Psa 62:4.