Al-Kahf

Verses 9–26[2] of the chapter retells the Christian folktale of the "People of the Cave".[3] A few young believers lived in a time when they were tortured for their beliefs. Upon the guidance of God, they fled the city where believers were persecuted, together with their dog, and took refuge in a cave where they fell asleep. When they awoke they found that the people of the city had become believers.

And recite (and teach) what has been revealed to thee of the Book of thy Lord: none can change His Words, and none wilt thou find as a refuge other than Him. Translation Yusuf Ali (Orig. 1938) [4]

The commentary by Ozma Nasir Makarim Shirazi says, "There is no room for diversity to enter into His Words and Knowledge. His Speech and His Knowledge is not like the speech and knowledge of human beings which, as a result of a new invention or information, has to be changed".[5]^:18:27 Ibn Kathir says this verse means of the words in the Quran, "no one can alter them, distort them or misinterpret them."[1]^:18:27

In verses 32–44 the surah discusses a parable of two men, one of whom had been given blessings from God and the other poor. The rich one wronged his soul and started showing off with his wealth and noble lineage.

And he had fruit, so he said to his companion while he was conversing with him, "I am greater than you in wealth and mightier in [numbers of] men."

— Quran, Al-Kahf (The Cave), Ayah 34[6][7]

Verse 36 explains that The rich man also told his companion that he doubted the existence of Judgment Day. At the end of the parable, God destroys what He had given the man.[8]

Imam Musa al-Kadhim narrates in Kitab al-Kafi that Ali would bequeath his companions to view this world with the vision of an ascetic because it dislodges its residents. Ali provides them with the parable of a lush, green garden with scented dew that accumulates under the blades of grass but then gets separated from it in the morning, as Allah has said, "Set forth to them the similitude of the life of this world: it is like the rain which We send down from the skies: the earth's vegetation absorbs it, But soon it becomes dry stubble, which the winds do scatter: it is (only) Allah Who prevails over all things. (18:45)." He advises his companions to "look at this world and the numerous things which cause you to wonder, and the scarcity of things that benefit you."[9]

The third main story within the chapter (verses 60–82[10]) is that of Musa (Moses) traveling to gain knowledge from another servant of God who is never mentioned by name, in tafsir of ibn Kathir he is called Al-Khidr.[11]

Finally, the surah mentions in verses 83–98[12] a man who traveled a great deal and reached the east and the west of the earth – namely, Dhul-Qarnayn. The Qur'an repeats the Syrian legend of a great king who helps a tribe of people build a massive wall of iron between two mountains. It goes on to say that this wall will be only destroyed on Judgement Day.[13] The wall may have reflected a distant knowledge of the Great Wall of China (the 12th-century scholar al-Idrisi drew a map for Roger of Sicily showing the "Land of Gog and Magog" in Mongolia), or of various Sassanid Persian walls built in the Caspian area against the northern barbarians, or a conflation of the two.[14]