Tafsir of Al-Mu'minoon 23:91

(Allah has not taken any son) due to His Exalted Highness being transcendent above need, and His Holiness being far removed from anyone being His equal.

(Nor is there with Him any god) who shares with Him, Glory be to Him, in divinity. (Then each god would have taken away what he created), meaning each would have exclusively seized what he created, becoming independent in its governance, and his kingdom would have been distinct from the kingdom of the other. (And some of them would have sought to overcome others); conflict and mutual struggle would have occurred between them, just as is the case among kings. The consequence of this is invalid, because it necessitates either the negation of the divinity of all of them, or the divinity of all but one, which is contrary to the premise. Furthermore, it necessitates that the sovereignty of all things not be in His Hand alone, which is invalid in itself, according to the proofs in theology and according to the opponent, who admits that the sovereignty of all things is exclusive to Him, as indicated by the previous questions and answers. So it is said. It is not hidden that the necessity in the conditional statement implied by the verse is habitual, not rational. Thus, it is said that the verse is an indication of a persuasive proof for monotheism, not a definitive one.

In al-Kashf, it has appeared to us, through the grace and support of Allah, that the verse is a luminous proof of His Oneness—Glory be to Him. Its formulation is: the reference point for all contingent beings is the Necessary Existent, exalted be His state and far removed is He from any multiplicity. As for a multiplicity of constituents or quantitative parts, its negation is evident, as it signifies contingency. As for multiplicity alongside unity in essence, it is likewise negated due to the need for a differentiator; the essence itself does not necessitate it, as they are united in it, thus contingency is necessitated. Furthermore, the two differentiators at the two poles would be attributes of perfection, for to be characterized by what is not a perfection is a deficiency. Therefore, they are both deficient, contingent, and in need of an external completer who is the Necessary Existent in truth. Likewise, the need for any perfection of existence necessitates contingency, as it implies there is within it something in potentiality and something in actuality, which requires composition and contingency.

From here, the scholars have said: The Necessary Existent by His essence is necessary in all His attributes; He has no pending state. With a difference in essence, it follows that the determiner would not be a determiner—that is, the god would not be a god. For if each of the contingent beings were independent in determining, it would necessitate two complete causes for a single effect, which is clearly impossible. Being a determiner who is a god necessitates need for him, and the other’s independence in determining necessitates being independent of him; thus, he would be a determiner and not a determiner at the same time. If they collaborated, it is like the case where neither of them is a determiner, and assuming they are both determiners, it involves helplessness in creation and need for the other. If each was specialized with some, despite the need for both being equal, it necessitates that this determiner be specified by a specifier that assigns that specific part to him by necessity. This is not the essence, for the need for them is equal, so there is no priority for determining from the standpoint of essence. Nor is it an effect of the essence, for it would then be contingent, and the discussion returns to the same point. Thus, the impossible results from the first two aspects: namely, the need for a differentiator other than the essence and its requirements, and the necessity of deficiency for each, because this differentiator is an attribute of perfection. Then, the specifier of each with that distinction is the external Necessary [Existent], not both of them.

The first impossibility is signaled by His saying: (Then each god would have taken away what he created). This is necessary upon the assumption of difference in essence and each being specialized with some; this category was specified because anything else is more obviously impossible. The second is signaled by His saying: (And some of them would have sought to overcome others), meaning either absolutely or in some respect. Thus, the one who overcomes is the god, or there is no god at all. This is necessary upon both assumptions of difference and unity and specialization and others. It is a completion of the proof from one aspect and a second proof from another. It has become clear, as clear as the dawn, that He—Glory be to Him—is the One, the Unique, whether His existence is considered an addition to His essence or not, and whether He is an Actor by choice or not. The proof of unity is not built upon the premise that He is an Actor by choice, as the Imam al-Razi—may his secret be sanctified—supposed. This is an expression over which the signs of investigation shimmer, and some objections might be raised against it, which are repelled by honest reflection.

What we have indicated regarding the understanding of a conditional proposition from the verse is very apparent according to what al-Farra’ chose. He said: “If idha (when/then) comes and is followed by the lam (emphatic l), then a law (if) is implied before it if it is not apparent,” such as: (Then each god would have taken away...). It is as if it were said: “If there were gods with Him as you claim, each would have taken away...” Abu Hayyan said: “Idha is a particle of response and recompense, and an oath is implied such that la-dhahaba (then would have taken) is its response.” The estimation is: "By Allah, idha..."—that is, if there were a god with Him, he would have taken. It is in the meaning of the emphatic future, as in His saying: (And if We send a wind and they see it yellow, they would remain...)—that is, la-yazallunna (they would surely remain), because idha necessitates the future tense. It is as you see. It is sometimes said that this idha is not the familiar word, but rather the conditional idha whose clause (to which it is added) has been omitted and replaced by tanwin (nunation), as in yawma’idhin (on that day). The original is: "If there were with Him a god, he would have taken..." The expression with idha is of the sort of debating with the opponent. It is said: (Each god)—since the negation is general, it benefits the inclusion of the genus. The ma in (what he created) is a relative pronoun whose referent pronoun has been omitted, as we have indicated.

It is permissible that it be an infinitive particle (masdariyyah), though it requires a type of straining that is not hidden. The negation of taking a son was not argued for, either due to the extreme obviousness of its corruption or because it is sufficient to rely on the proof established for the negation of there being a god with Him, Glory be to Him, based on the saying that the son of a god must be a god, since the son is of the species and substance of the father, though there is debate in this.

(Exalted is Allah above what they describe)—an exaggeration in declaring Him transcendent above a son and a partner. Ma is a relative pronoun, and it is permissible that it be an infinitive particle. It is recited tasifun (you describe) with the second-person ta’.