Tafsir of An-Naba' 78:23

"Lāithīn" (abiding) therein, meaning dwelling in Hell, remaining in it continuously. It is a circumstantial qualifier (hāl) implied by the hidden pronoun in "lil-ṭāghīn" (for the transgressors).

Abdullah, Alqamah, Zayd ibn Ali, Ibn Waththab, Amr ibn Sharahbil, Ibn Jubayr, Talhah, Al-A‘mash, Hamzah, Qutaybah, and Rawḥ read it as "labithīn" without an alif after the lām, a form which carries an intensity not present in "lāithīn." Abū Ḥayyān stated that the form "fā‘il" denotes one from whom an action has originated, while "fa‘il" denotes that this is his inherent state, like "ḥādhir" (cautious) and "ḥadhir" (wary).

His statement, "aḥqāban" (ages), is a temporal adverb for their abiding. It is—like "aḥqub"—the plural of "ḥuqb" (with a damma on the ḥāʾ, or two dammas). According to what is narrated from Al-Hasan, it denotes an unlimited period of time, and some linguists interpret it similarly as "ad-dahr" (time/an age).

Sa‘īd ibn Manṣūr and Al-Ḥākim (who authenticated it) narrated from Ibn ‘Abbās that he said: "One ḥuqb is eighty years." Al-Bazzār narrated the same from Abū Hurayrah, Ibn Jarīr from Ibn ‘Abbās, and Ibn al-Mundhir from Ibn ‘Umar. It is also narrated from a group among the predecessors, but they added that each day of it—meaning here—is equivalent to a thousand years of the years of this world. Al-Bazzār, Ibn Mardawayh, and Al-Daylamī narrated from Ibn ‘Umar in a marfū‘ (attributed to the Prophet) tradition that it is "more than eighty years; each year is three hundred and sixty days, and each day is a thousand years of what you count." Others have said it is forty years. Ibn Mardawayh recorded a marfū‘ hadith on this from ‘Ubādah ibn al-Ṣāmit, while some linguists claimed it is seventy thousand years. Many have chosen to interpret it as "an age" (ad-dahr).

Regardless of the specific duration, the meaning is: abiding therein for successive ages, where every time an age passes, another age follows it. The implication of succession in its usage is evidenced by its derivation, for it comes from "al-ḥaqībah," which is that which is fastened behind the rider; things that are successive follow one after another. Thus, there is nothing in the verse indicating the exit of the disbelievers from the Fire or their lack of eternal residence in it, due to the succession implied in its usage.

Furthermore, a morphological form denoting a small quantity does not negate infinity; there is no difference between the succession of many ages reaching infinity and the succession of few ages doing the same. It has been said that the form here is shared between small and large quantities, as "ḥuqb" has no standard plural form for a large quantity; therefore, the context here necessitates it meaning a large quantity. This has been countered by the claim that it does have a plural for a large quantity, which is "al-aḥqub," as mentioned by Al-Rāghib. However, what I have seen in his Mufradāt is that "al-ḥuqb" is the plural of "al-ḥiqbah," which is explained as eighty years.

Yes, it has been said that this [interpretation of permanence] is contradicted by reports stating that people from the inhabitants of the Fire will be brought out of the Fire and brought near to Paradise, until they inhale its scent and see what Allah has prepared for His believing servants therein, at which point they will be told: "Turn them away from it, for they have no share in it." They will then be returned to the Fire with a sense of regret unlike any experienced by those before or after them. This is countered by the argument that, even if it were authentic, it would only contradict the notion of eternal residence if the exit spanned an entire "ḥuqb." If it occurs within only some parts of a "ḥuqb," there is no contradiction, for the succession of ages as a whole remains.

Even if we were to grant [that the exit is longer], this expulsion—which is followed by a return for increased punishment—is more severe than the mere abiding in the Fire. The speech is a matter of taghlīb (dominance/generalization), and it does not involve combining the literal and the metaphorical. Furthermore, if it were found that the verse necessitates a limit and an exit from the Fire, even after a long time, such an understanding would be contradicted by explicit, unambiguous declarations to the contrary, such as the verses on eternal residence and His saying: "And they will not be able to leave it, and for them is a lasting punishment," and other similar verses.