Tafsir of Al Imran 3:116

(Indeed, those who disbelieve—never will their wealth or their children avail them against Allah at all.)

This is an affirmation of that [preceding statement], and for this reason, it is disconnected [from what precedes it].

The intent behind the "those who" (al-mawsul) refers either to all disbelievers, for they boasted of wealth and children, as they said: "We are more abundant in wealth and children, and we shall not be punished." Allah the Exalted refuted them with what you see. Alternatively, it refers to Banu Qurayza and Banu al-Nadir, as their reliance was upon wealth and children. This is narrated from Ibn Abbas—may Allah be pleased with both of them. It has also been said: [it refers to] the polytheists of Quraysh. Perhaps the one who argues for generality—which is the apparent meaning—says that the aforementioned groups are included primarily.

The intent of "avail" (al-ighna') is "warding off." It is said: "He availed him," meaning he warded off a harm from him that would have descended upon him were it not for that. That is to say: their wealth, upon which they relied in [their] important affairs, and those who are more hoped for and greater in their estimation, namely their children, will not ward off from them any slight part of Allah's punishment on the Day of Resurrection.

Some said: The intent of "avail" is "sufficiency." It is said: "This does not avail you," meaning it does not suffice you and does not benefit you. The particle "min" (from) is for substitution or initiation, and "shay'an" (at all/a thing) is an absolute object (maf'ul mutlaq), meaning: that will not suffice them from Allah's punishment in any way of sufficiency. According to the first interpretation of "avail," making this its true meaning rather than the former is achieved through inclusion (tadmin), and the object-status here is apparent due to the verb becoming transitive [in that sense].

(And those are) — that is, those described with disbelief, by reason of their disbelief — (the companions of the Fire) — meaning those who permanently abide therein, which is the meaning of "companions" (ashab) by convention.

(They will abide therein eternally) — this is a confirmation of what is intended by the first sentence. The nominal sentence was chosen to signify perpetuity and continuity, and the prepositional phrase was placed first [before the verb] to preserve the rhyme scheme of the verses.