Tafsir of Fatir 35:7

(Those who disbelieve, for them is a severe punishment) because of their disbelief, their response to the call of Satan, and their following of his footsteps. The indetermination of "punishment" (in the Arabic text) may be to denote its magnitude regarding its duration, as if it were said: For them is a severe, everlasting punishment.

(And those who believe and do righteous deeds, for them is forgiveness) great (and a great reward) limitless, because of the aforementioned faith and righteous deeds.

"Those who disbelieve" is an initial (mubtada') whose predicate is "for them is a punishment," and likewise is "those who believe" and "for them is forgiveness," etc. Some have permitted "Those who disbelieve" to be in the genitive case as a substitute for "the companions of the Blaze," or as an adjective for it; or in the accusative case as a substitute for "his party," or as an adjective for it; or in the nominative case as a substitute for the pronoun in "(in order) to be," but all of these weaken the eloquence of the composition, as is not hidden from the intelligent.