This is another excerpt from Bill Warner’s book Abridged Koran where the verses of Koran are arranged in their chronological order and provided with facts from prophet Muhammad’s life, giving context for them.
CHAPTER 4 (Continued)
As to the question about the mighty traveler:
18:83 They will ask you about Zul-Qarnain [Alexander, the Great]. Say: I will recite to you an account of him. We established his power in the land and gave him the means to achieve any of his aims. So he followed a path, until, when he reached the setting of the sun, he found it setting in a muddy pond. Nearby he found a people. We said, “Zul-Qarnain, you have the authority to either punish them or to show them kindness.”
18:87 He said, “Whoever does wrong, we will certainly punish. Then he will be returned to his Lord, Who will punish him with a terrible punishment. But whoever believes and does good deeds shall be given a wonderful reward, and We will give them easy commands to obey.”
18:89 Then he followed another path, until, when he came to the rising of the sun, he found that it rose upon a people to whom We had given no protection from it. He left them as they were. We knew everything about him. Then he followed another path until, when he reached a place between two mountains, he found a people living in a valley who could scarcely understand a single word. They said, “Zul-Qarnain, the people of Gog and Magog are terrorizing the land. May we pay you tribute so that you will build a strong barrier between us and them?”
18:95 He said, “The power which my Lord has given me is better than your tribute. Help me, therefore, with manpower. I will build a strong barrier between you and them. Bring me blocks of iron.” Later, when he had filled the gap between the two mountains, he said, “Blow with your bellows!” When it had become as red as fire, he said, “Bring me molten lead to pour over it.” So the people of Gog and Magog were unable to climb over the barrier or to go through it. He said, “This is a mercy from my Lord, but when my Lord’s promise comes to pass, He will destroy it, because my Lord’s promises always come true.”
The question—what is the spirit?
17:85 They will ask you about the spirit [probably the angel Gabriel]. Say: The spirit is commanded by my Lord, and you are given only a little knowledge about it. If We wished, We could take Our revelations away from you. Then you would find no one to intercede with us on your behalf except as a mercy from your Lord. Surely His kindness to you is great