Tafsir of Ar-Rum 30:10

"Then the end..."

• "The end" (ʿāqibah): It is read both in the accusative (naṣb) and the nominative (rafʿ).
• "The worst" (as-sūʾā): This is the feminine form of al-aswaʾ (the ugliest/worst), just as al-ḥusnā is the feminine of al-aḥsan (the best).
• The meaning: They were punished in this world with destruction, and then their end was "the worst." The noun is used in place of the pronoun—meaning the punishment that is the worst of all punishments in the Hereafter, which is Hell, prepared for the disbelievers.
• "That they denied" (an kadhdhabū): This is in the sense of "because they denied" (li-anna). It is also permissible for an to mean "that is" (ay), because when the interpretation of "doing evil" is denial and mockery, it takes on the meaning of speech, similar to "he called out" or "he wrote," and the like.
• Another perspective: "They committed the worst" (asāʾū as-sūʾā) means they committed the sin that is the worst of all sins. "That they denied" (an kadhdhabū) is an explanatory apposition (ʿaṭf bayān) for it. The predicate of kāna is omitted—just as the answer to lammā and law is omitted—to intend ambiguity.

"Allah begins creation, then He repeats it; then to Him you will be returned."