And He it is Who has made you successors in the land and raised some of you above others by (various) grades, that He might try you by what He has given you; surely your Lord is quick to requite (evil), and He is most surely the Forgiving, the Merciful.

Or like utter darkness in the deep sea: there covers it a wave above which is another wave, above which is a cloud, (layers of) utter darkness one above another; when he holds out his hand, he is almost unable to see it; and to whomsoever Allah does not give light, he has no light.