And you might see the sun when it rose, decline from their cave towards the right hand, and when it set, leave them behind on the left while they were in a wide space thereof. This is of the signs of Allah; whomsoever Allah guides, he is the rightly guided one, and whomsoever He causes to err, you shall not find for him any friend to lead (him) aright.

Until when he reached the place where the sun set, he found it going down into a black sea, and found by it a people. We said: O Zulqarnain! either give them a chastisement or do them a benefit.