Tafsir of Ash-Shu`ara' 26:209

(ذكرى) (A reminder): It is in the accusative case as a state (hal) from the pronoun in (منذرون) (warners), according to al-Kisa’i; and as a verbal noun (masdar), according to al-Zajjaj.

Regarding the state: one either presumes it means "possessors of a reminder," or "those who remind," or it remains as it is literally, for the sake of hyperbole.

Regarding the verbal noun: its governing factor (amil) is (منذرون), because in the sense of "we remind," it means "they are mentioned in a reminder" (i.e., a warning).

Al-Zamakhshari permitted that it be a causal object (maf’ul lahu), in the sense that they are warned for the sake of exhortation and reminding. He also permitted it to be in the nominative case as the predicate of an omitted subject, meaning "This is a reminder," with the sentence being parenthetical; or as an adjective, meaning "warners possessors of a reminder," or "reminders," or that they were made into the very reminder itself as a form of hyperbole, due to their exaggeration in reminding and their eloquence therein.

He also permitted it to be connected to (أهلكنا) (We destroyed) as a causal object. The meaning would be: "We did not destroy any town, being unjust, except after we established the proof against them by sending warners to them, so that their destruction would be a reminder and a lesson to others, that they might not disobey as they disobeyed." He then said: "This is the angle to be relied upon." He clarified this in al-Kashf by saying: "Because it is a threat to the mockers, and [an indication] that they deserve to be made an example and a lesson to others, like the previous nations, for they did as they did—mocking and denying—and were thus recompensed." In that case, the discourse becomes coherent.

This was critiqued by the argument that the school of the majority is that "ma" and "illa" do not govern anything after them unless it is an exception, an exception from, or a dependent of the former that does not rely upon the particle. The causal object is none of these three, so it is not permissible for it to be connected to "We destroyed." The permissibility of this can be derived according to the school of al-Kisa’i and al-Akhfash, even though they did not grammatically establish it as a causal object here, due to the artificiality in doing so. The matter of coherence is easy, as is not hidden.

(وما كنا ظالمين) (And We were not unjust): Meaning, it is not our nature, according to the requirements of wisdom, for that which appears as injustice—if it were to come from someone else—to emanate from Us, such as destroying anyone before warning them, or punishing those who are unjust. To negate that this is of His nature—Exalted is His majesty—He said: (وما كنا) (And We were not), rather than "And We do not act unjustly."