[Whenever] He sends down water from the sky, and [once-dry] river-beds are running high* according to their measure, the stream carries scum on its surface;* and, likewise, from that [metal] which they smelt in the fire in order to make ornaments or utensils, [there rises] scum. In this way does God set forth the parable of truth and falsehood: for, as far as the scum is concerned, it passes away as [does all] dross; but that which is of benefit to man abides on earth. In this way does God set forth the parables