He sends down water (rain) from the sky, and the channels flow (with water), each by its measure: But the flood carries away (to clean) the foam that comes up to the surface. And like this, from the (ore) which they heat (to melt) in the fire, to make ornaments or pots (and pans) from it, also there is a scum (or foam). Thus Allah clearly shows forth truth and vanity for the scum disappears when it is thrown out; Whereas what remains is for the good of mankind on the earth. Thus Allah does set forth examples (parables).