Tafsir of Az-Zumar 39:72

(It will be said: "Enter the gates of Hell, abiding therein") meaning: your abiding therein is decreed. As for the speaker, it is possible that it is the keepers [of Hell], and their mention was omitted because they are known from what preceded. It is also possible that it is others, and they were not mentioned because the intention is to state this terrifying pronouncement without regard for who said it. Some eminent scholars have said: The speaker was left indefinite to increase the terror of the spoken word.

(So how wretched is the lodging of the arrogant)

The al (definite article) in it—whether it be the definitive particle or a noun describing the genus—fulfills the requirement for the subject of ni'ma and bi'sa (the verbs of praise and blame). The specified object of blame is omitted, relying upon its previous mention, meaning: "So how wretched is their lodging—Hell."

The expression "lodging" (mathwa) is used on account of the word "abiding therein" (khalidina). In the expression "the arrogant," there is an indication that their entry into the Fire is due to their arrogance in accepting the Truth and submitting to the warning messengers, peace and blessings be upon them. This is equivalent in meaning to attributing it to disbelief (kufr). It does not contradict attributing it to the decree of the punishment having been preceded against them, for the judgment of the Exalted and His decree regarding their entry into the Fire is not except because of their arrogance and disbelief resulting from their poor choice, which was known to Him, the Exalted, in eternity. Likewise is His saying, the Almighty and Majestic: "I will surely fill..."

Thus, there are two causes: a proximate one and a remote one. Attributing the cause to one does not contradict attributing it to another. So take note and reflect.