The figure is taken from the great tank or reservoir upon which Eastern cities often depended for their supply of water. The beginning of strife is compared to the first crack in the mound of such a reservoir. At first a few drops ooze out, but after a time the whole mass of waters pour themselves forth with fury, and it is hard to set limits to the destruction which they cause.
Before it be meddled with - literally, “before it rolls, or rushes forward.”