Tafsir of Al-Kahf 18:5

"They have no knowledge of it"—that is, regarding His (Exalted and Almighty is He) taking a son—"nor do their fathers":

The phrase "no knowledge" (min ‘ilmin) is in the nominative position, either as an initial subject (mubtada’) or as a subject of an implied verb due to the precedence of the prepositional phrase (zarf). The "min" is an extra particle used for emphasizing the negation. The sentence describes their state or is an initiating statement concerning the condition between them in their utterance; it means they have absolutely no knowledge of that matter at all. This is not because they missed a path to knowledge despite the existence or possibility of the object of knowledge, but rather because it is impossible in itself, and alongside impossibility, the acquisition of knowledge cannot be established.

Some have argued that the pronoun "it" (bihi) refers to the "son," and the lack of knowledge applies to this, as well as the status of the sentence mentioned above. Al-Mahdawi claimed that, in this reading, the sentence is an adjective for "son," but this is baseless. It is also permissible for the pronoun to refer to the "saying" understood from "they say" (qalu), meaning: their saying that does not stem from knowledge, reflection, or consideration of what is permissible or impossible for Him, the Almighty. Al-Tabari said: It refers to Allah, the Almighty, in the sense that they have no knowledge of what is permissible or impossible for Him.

"Nor do their fathers": those who said the same thing, attributing adoption to Him, the Almighty. Exposure to the negation of knowledge regarding them is because they were the role models for these [latter people].

"Grave is the word...": that is, this utterance of theirs regarding disbelief and fabrication is grave, because it involves attributing to Him, the Almighty, what is in no way fitting for His majesty, the Almighty. "Grave" (kaburat)—as well as everything on the measure of fa‘ula—is predicated upon the damma (as a static form), whether as a prepositional marker or transformed from fa‘ala or fa‘ila. Al-Akhfash and Al-Mubarrad were of the view that it belongs to the category of astonishment (ta‘ajjub); thus, the subject here is a pronoun referring to His saying "taking..." etc., interpreted as "the utterance," and "word" (kalimatan) is in the accusative as a specifier (tamyiz). It is as if it were said: "How grave it is as a word!"

His saying, "that comes out of their mouths": is an adjective for "word," serving to express the enormity of their audacity in uttering it and bringing it forth from their mouths. For often, the soul is whispered to by Satan with things that the tongue cannot utter, nor can the mind even turn toward them, so how much more [is this the case] with such an abominable thing!

Al-Farisi and most grammarians were of the view that it belongs to the category of ni‘ma and bi’sa (verbs of praise and blame), thereby taking all its rules: such as its subject being defined by al-, or in a genitive construction with something defined by it, or a pronoun clarified by a specifier. From here, it is permissible that the subject here is a pronoun [referring back to] "word," which is also a specifier, and the sentence is its adjective; there is no harm in describing the specifier in the category of ni‘ma and bi’sa. Abu Hayyan and others allowed for it to be an adjective for an omitted word, which is the specific object of blame (al-makhsus bi al-dhamm), meaning: "Grave is the word, a word coming out of their mouths." The apparent stance of Al-Akhfash suggests a difference between the two schools of thought. In Al-Tashil, it is stated that it is from the category of ni‘ma and bi’sa, containing the meaning of astonishment, and the intent here is to magnify the matter in the hearts of the listeners. This clearly indicates that there is no difference between them, and the words of some Imams lean toward this. It has been said that it is in the accusative as a state (hal), but its condition is clear [as weak]. Naming this a "word" is like naming a poem by that term.

It has been recited as "kaburta" with a quiescent ba’, which is the dialect of Tamim; in such verbs, the vocalization of the middle radical (‘ayn) with damma, its quiescence, and the transfer of its movement to the first radical (fa’) have all occurred. Al-Hasan, Ibn Ya‘mur, Ibn Muhaysin, and Al-Qawas (from Ibn Kathir) read "kalimatu" in the nominative case as the subject; the accusative is more eloquent and emphatic.

Al-Nazzam used this verse to argue that speech is a physical body, because it is described therein as "coming out," which is a property of bodies. The response to this is that what truly comes out is the air that carries it, and attributing it to the speech, which is a quality, is metaphorical. This has been countered by noting that Al-Nazzam, who asserts the corporeality of speech, argues that it is the air shaped by sound, not just a quality. His deduction is based on the premise that the literal is the primary meaning; however, the disagreement is purely verbal and carries no [meaningful] outcome.

"They say nothing but a lie": that is, they say nothing regarding that matter except a lying statement that can in no way come under the possibility of truth at all. The two pronouns refer to "them" and "their fathers."