Tafsir of At-Tur 52:15

"Is this magic?" This is a rebuke and a scorn directed at them, as they used to call the revelation that warned them of this "magic." It is as if it were said: "You used to call the revelation that warned you of this 'magic'; is this, which confirms it, also magic?" The predicate (magic) is brought forward because it is the object of the denial and the pivot of the rebuke.

"Or do you not see?" Meaning, are you blind to what you have been informed of, just as you were blind in the world to the news? The "Fa" (in Afasihrun) indicates what has been mentioned. This is because, since the particle requires a conjunctive phrase upon which the sentence—that is, "Is this magic?"—can be predicated, and since this sentence was introduced as a rebuke, similar to "Is this the Fire...", it was necessary to estimate a preceding clause in a way that makes the sequence valid and is indicated by the context. Thus, it is estimated as "You used to say..." and this is evidenced by His saying, "In their vain discourse they play," and His saying, "This is the Fire which you used to deny."

In Al-Kashf, it is stated that this is analogous to when you argue with a proof and the opponent says, "This is false," and then you bring a proof clearer than the first—one that silences them—and you say, "Is this false?" You reproach them by imposing the requirement that their first statement was false. In such a case, it is permissible to estimate the speech in the sense of, "Do you say this is false?" And it is not estimated otherwise, because it is built upon the opponent's speech, which is more eloquent.

As for the "Am" (or), it is, as is apparent, munqati'ah (disjunctive). In Al-Bahr, it is stated that when it was said to them, "This is the Fire," they paused at the two aspects from which doubt could enter regarding whether it is the Fire: either there is magic that obscures the essence of the matter, or there is an impairment in the observer. The apparent meaning is that "Am" is treated as mu'adilah (conjunctive/equative), and the first interpretation is deeper in meaning.