Tafsir of Yunus 10:81

(So when they cast)—meaning what they cast of rods and ropes, and they terrified the people and brought a (great sorcery)—** (Moses said)** to them, unconcerned by them and what they had produced: (What you have brought is sorcery).

As for (What), it is a relative pronoun acting as the subject (mubtada’), and (sorcery) is the predicate (khabar). The Al (the definite article) therein is for the generic (lil-jins), and the definiteness is for the sake of restriction (qasr) by way of isolation (ifrad). That is: "That which you have brought is the [true] sorcery, not what Pharaoh and his assembly termed as sorcery from the signs of Allah Almighty." It is for the genus.

It has been narrated from Al-Farra’ that the Al is for reference to a previous mention (lil-‘ahd), due to the mention of "sorcery" appearing in the statement of the Exalted: (Indeed, this is a sorcery). This has been countered by the argument that for it to be for reference, there must be an identity of essence between the preceding and the subsequent, as in: (We sent a messenger to Pharaoh, and Pharaoh disobeyed the messenger). There is no such identity here, for the preceding sorcery is that which Moses (peace be upon him) brought, whereas this is what the sorcerers brought.

Some people reject the requirement of essential identity, claiming that identity in genus is sufficient. They have said regarding the verse: (And peace be upon me), that the Al is for reference, even though the "peace" bestowed upon Jesus (peace be upon him) is not identical in essence to the "peace" bestowed upon John (peace be upon him). However, the manifest view is that identity is required, and identity in genus is insufficient. Otherwise, it would be valid to say—upon seeing a man and honoring "the man," where the first is Zayd and the second is ‘Amr—that the Al is for reference because the identity in genus is apparent. We have not found anyone who says this; indeed, I do not believe anyone’s soul would suggest it to them. The case in the verse is of this sort; in fact, the divergence between the antecedent and the subsequent is even more apparent, for the first is a declarative/alleged sorcery and the second is actual. As for "peace," in their example, it is identical, and the plurality of those upon whom it is bestowed does not make the "peace" itself multiple in convention, and philosophical hair-splitting is not to be heeded in such matters.

Some investigators have mentioned that the position that the definite article is for reference, while simultaneously claiming that restriction (qasr) is derived from it, is contradictory, because restriction only occurs when the article is for the genus. Yes, if there was no intention of a specific antecedent for the mentioned indefinite noun, and then it was made definite, this does not contradict the generic nature of the article, because the indefinite equals the definition of the genus. In that case, the definition for reference does not contradict restriction, even if their discourse superficially suggests otherwise; let this be scrutinized. I say: Al-Farra’'s claim of reference here is something that should not be heeded. Perhaps he intended the genus, even if he expressed it as "reference," based on what Jalal al-Suyuti mentioned in Ham‘ al-Hawami‘, narrating from Ibn ‘Usfur that he said: "It is not far-fetched in my view that the Alif and Lam for the definition of the genus be called 'reference-like,' because genera are known to the rational from the moment they understand them, and reference is the precedence of knowledge." Abu al-Hajjaj Yusuf ibn Ma‘zuz claimed that Al can only be for reference and interpreted it in a way similar to what was mentioned, but the manifest nature of the reasoning does not support that.

‘Abdullah read it as (sirhun)—indefinite—and Ubayy read it as (ma ataytum bihi sirhun). The speech in this is also useful for restriction, but by way of contextual implication (ta‘rid) due to its occurrence in opposition to their saying: (Indeed, this is a manifest sorcery).

It is permissible regarding (What) in all these recitations that it be interrogative, and (sorcery) is the predicate of an elided subject. Abu ‘Amr and Abu Ja‘far read: (A-al-sirhu), with the Alif pronounced and lengthened as an interrogation. In this case, "What" is interrogative, raised as a subject, and (you have brought) is its predicate; and (sorcery) is the predicate of an elided subject, or a subject whose predicate is elided—i.e., "What a grave thing you have brought; is it sorcery, or is sorcery it?" It may also be that "sorcery" is an appositive (badal) to "What," just as you would say: "What do you have, a dinar or a dirham?" Or "What" might be in the accusative case by an elided verb estimated after it, meaning: "What thing have you brought?" and (you have brought) acts as an explanation for it. In (sorcery), both of the aforementioned interpretations apply.

It is also permissible that it is a relative pronoun acting as a subject, and the nominal sentence—i.e., "Is it sorcery, or is sorcery it?"—is its predicate. This involves predicating with an insha'i (non-declarative) sentence. It is not permitted under this estimation for it to be in the accusative by an elided verb explained by what is mentioned, because that which does not act (as a verb) does not explain an actor.

(Indeed, Allah will invalidate it)—meaning He will utterly annihilate it by what He manifests at my hands of miracles, so that no trace of it remains at all; or He will manifest its falsity and corruption to the people. The Sin is for emphasis. (Indeed, Allah does not rectify the work of the corrupters)—meaning their genus, absolutely, so the sorcerers are included in this primarily. It is also permissible that the "corrupters" refers to the ones addressed, making it a case of using the noun in place of the pronoun to register them as corrupt and to signal the cause of the ruling. The sentence is an appendage to provide the rationale for what preceded it and to emphasize it. The intent by "not rectifying" is the lack of establishing it or the lack of strengthening it with divine support, not the lack of making the corrupt "rectified," for it is obvious that such a thing cannot be. That is, He (Exalted is He) does not establish the work of the corrupters nor does He sustain it; rather, He removes and annihilates it, or He does not strengthen or support it; rather, He manifests its falsity and makes it known.

The verse has been used as evidence that sorcery is corruption and deception that has no reality. You know that there is a debate regarding the categorical statement that sorcery has no reality. The truth is that some of it has a reality, and some of it is false imagination, which is termed sha‘badhah (legerdemain) and sha‘wadhah (conjuring).