This means that the soldiers would tear down the city walls and drag the pieces to river. AT: "will destroy the city and drag the stones to the river with ropes" (See: [[rc://en/ta/man/translate/figs-explicit]])
This is an exaggeration to describe how completely they will destroy the city. The would not literally sweep away every small stone from the city. AT: "until the city is completely destroyed" (See: [[rc://en/ta/man/translate/figs-hyperbole]])