Surat Al-Kahf (The Cave) - سورة الكهف

: And they ask you about Dhul-Qarnain. Say: "I shall recite to you something of his story."

: Verily, We established him in the earth, and We gave him the means of everything.

: So he followed a way.

: Until, when he reached the setting place of the sun, he found it setting in a spring of black muddy (or hot) water. And he found near it a people. We (Allah) said (by inspiration): "O Dhul-Qarnain! Either you punish them, or treat them with kindness."

: He said: "As for him (a disbeliever in the Oneness of Allah) who does wrong, we shall punish him; and then he will be brought back unto his Lord; Who will punish him with a terrible torment (Hell).

: "But as for him who believes (in Allah's Oneness) and works righteousness, he shall have the best reward, (Paradise), and we (Dhul-Qarnain) shall speak unto him mild words (as instructions)."

: Then he followed another way,

: Until, when he came to the rising place of the sun, he found it rising on a people for whom We (Allah) had provided no shelter against the sun.

: So (it was)! And We knew all about him (Dhul-Qarnain).

: Then he followed (another) way,

: Until, when he reached between two mountains, he found, before (near) them (those two mountains), a people who scarcely understood a word.

: They said: "O Dhul-Qarnain! Verily! Ya'juj and Ma'juj (Gog and Magog) are doing great mischief in the land. Shall we then pay you a tribute in order that you might erect a barrier between us and them?"

: He said: "That (wealth, authority and power) in which my Lord had established me is better (than your tribute). So help me with strength (of men), I will erect between you and them a barrier.