Tafsir of Fussilat 41:19

(And the Day the enemies of Allah are gathered to the Fire): This is the commencement of an explanation of their deferred punishments, following the mention of their immediate punishments. They are described as "enemies of Allah the Exalted" to disparage them and to signal the cause of the various forms of torment that will befall them. It has been said: the intended meaning is the disbelievers from the first and the last.

This is countered by the fact that His, the Exalted’s, forthcoming statement: (...among nations which had passed on before them of jinn and mankind) is virtually explicit in intending the familiar disbelievers. Regarding His, the Exalted’s, statement: (to the Fire), it has been said: it means to the place of reckoning, and it is expressed as "the Fire" to signal that the Fire is the ultimate consequence of their gathering and that they are on the verge of entering it. There is no impediment to maintaining it in its literal sense, assuming that the testimony is multiple; thus, their limbs bear witness against them at the place of reckoning at one time, and at the edge of Hell at another.

(Day) is either in the accusative case due to an implied udhkur (remember), and it is coordinated with His, the Exalted’s, statement: (Say: "I have warned you of a thunderbolt..."), or it is an adverbial modifier for an implicit, delayed verb that has been omitted, suggesting that the expression is insufficient to detail it. It has also been said: it is an adverbial modifier for what is indicated by His, the Exalted’s, statement: (...they will be driven in ranks).

19

(i.e., the first of them is held back for the last of them so that they may join one another). This is a metonym for their great number. It has also been said: they are driven and pushed toward the Fire. The fa (in faham) is explanatory. Zayd ibn Ali, Nafi’, al-A’raj, and the people of Medina recited (nahshuru) with the nun, with (a’da’a) in the accusative case; and al-A’raj recited the shin with a kasra. It was also read (yahshuru), constructed for the active subject—which is Allah the Exalted—with the accusative of (a’da’a Allah). And His, the Exalted’s, statement: [...]