Tafsir of Al-Kahf 18:10

(When) — the adverbial particle is a complement to (a marvel) or to (they were), or it is to be understood as [the object of an implicit] "Remember." It is not permissible for it to be an adverb of time for "You supposed," because their "supposing" did not occur at that time—that is, when (the youths took refuge in the Cave) and adopted it as a shelter and a place for themselves.

"The youths" (al-fityah) is a plural of paucity for "youth" (fata). As al-Raghib and others have stated, it refers to the fresh or tender among young men; it is also pluralized as fityan. Ibn al-Sirraj said: It is a collective noun. Others have said: It is the plural of fata, like sabi (boy) and sibyah (boys), and this is favored by the frequency of such patterns. What is meant by them are the People of the Cave. The preference for using the explicit noun over a pronoun is to confirm the state of "youthfulness" they were in; for it is narrated that they were young men, sons of the nobles and dignitaries of Rome, wearing gold collars and bracelets, and possessing long locks of hair. It is also said [that the noun was used] because the "taking refuge in the Cave" is a branch of their act of seeking refuge, so it is not appropriate to consider them [the youths] together with it before it is explained. The apparent meaning is with the pronoun, but it is not so with this explicit noun, even if the definite article al- in it is for reference.

(So they said, "Our Lord, grant us from Yourself) — that is, from Your presence — (a mercy) — either great, or a specific kind of mercy; the tanwin is for magnification or for specification — (a mercy) — and "from" (min) is for origination, attached to "grant us." It is also permissible for it to be attached to an implicit state relative to "mercy," having preceded it because it is indefinite; if it had followed, it would have been an adjective for it. Mercy has been interpreted as forgiveness, provision, and safety, but it is better to interpret it as that which encompasses this and more. In mentioning "from Yourself," there is an indication that this is a matter of pure grace, not an obligation; as if they said, "Our Lord, bestow upon us a mercy."

(And prepare for us from our affair) — that is, the affair in which we are engaged, namely, migrating from the disbelievers and persevering in Your obedience — (guidance) — that is, attainment of the path that leads to the desired goal and direction toward it. Abu Raja’ read it as rushdan (with a damma on the ra and a sukun on the shin), and the meaning is one, though the reading of the majority is more consistent with the verse endings. Al-Raghib held that the meaning is unified, saying: Rushd (with two fatha vowels) is the opposite of ghayy (error), and it is used in the sense of hidayah (guidance), as is rushd (damma followed by sukun). Some have said: Rushd (with two fatha vowels) is more specific than rushd (damma), for the latter is used for both worldly and otherworldly matters, whereas the former is used only for otherworldly matters. However, there is a contradiction in this to what Ibn Atiyyah mentioned, for he said: This supplication of theirs was regarding their worldly affairs, and its wording necessitates that. They were already certain of the guidance of the Hereafter and its mercy. Every believer should model their supplication regarding their worldly affairs after this verse, for it is sufficient. It is also possible that "mercy" refers to the mercy of the Hereafter. Indeed, there is room for debate in what he said; it is better to make the supplication general, covering both worldly and otherworldly affairs, even if the verse that follows makes it appear specific to the former.

The prepositional phrases "from our affair" and "guidance" are both attached to "prepare." If their meanings differ—in that the first is for [the sake of] the cause and the second is for origination—then there is no issue; but if both are for the sake of the cause, the validity of the attachment requires the well-known [grammatical] answer.

The fronting of the two prepositional phrases before the direct object is to demonstrate care for them and to highlight the desire for the final object. The same applies to the fronting of "from Yourself" before "mercy" in the estimation that it is attached to "grant us." The fronting of the first prepositional phrase over the second is to signal from the very beginning that the object requested is deeply desired by them. It is said that the speech is based on "abstraction" (tajrid), which is to extract from a person possessing a quality another person like him as a form of hyperbole, as if he reached a rank of perfection such that it is possible to take another from him—like "I saw in you a lion"—meaning: "Make our entire affair guidance."