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.
Meaning:-
In the deep sea: there covers it a wave above which is another wave:This is another scientific fact mentioned in the Quran: the existence of underwater waves, like layers.
Light: guidance or Wisdom.