Tafsir of Al-Kahf 18:109

Say: "If the sea were ink" — meaning the genus of the sea — "for the words of my Lord" — meaning prepared for the writing of His words, the Almighty. What is intended by these words, as narrated from Qatada, is the knowledge of the Glorified One and His wisdom, the Almighty. "The sea would surely be exhausted" — despite its vastness, and nothing of it would remain, because it is finite — "before the words of my Lord are exhausted" — due to their being infinite.

"And if We brought the like of it as an addition" — as aid and increase, because the sum of two finite things is finite; indeed, everything that enters into existence, whether successively or collectively, is finite by the proof of application and other proofs. This speech, from His side, the Exalted is His majesty, is not included within the commanded speech [to the Prophet]; rather, it was brought to verify its content and attest to its implication in the most perfect way. The "wa" (and) is for connecting the sentence to its counterpart—the initiated sentence that corresponds to it, which is omitted because the mentioned part serves as a clear indication of it. That is: "The sea would be exhausted before the words of my Lord are exhausted if We did not bring the like of it as an addition; and if We brought the like of it as an addition..." The discussion regarding the answer to "if" (law) is well-known. His saying, "before they are exhausted," is not intended to imply that there is an exhaustion [of His words] in the whole, neither realized nor estimated, because the intention of it is: "The sea would be exhausted while they remain." However, He shifted to the standard [expression] for the sake of pairing, meaning that which does not become exhausted in the estimation of common intellects becomes exhausted, unlike [His words] which do not. And however much you suppose of addition, it is likewise.

The example of the genus is common regarding many instances, each of which is supposed as an addition. This, as stated in al-Kashshaf, is more eloquent from one perspective than His saying: "And the sea [to which] seven seas are added after it." Yet that [other verse] is more eloquent from another perspective, which is the point of specifying that [specific] number; there is no intention to specify the count. Furthermore, it contains an increased depiction of what is established in the beliefs of the common people, for they believe there are seven [seas], such that when they exaggerate about something impossible to reach, they say, "It is behind seven seas." In attributing the "words" to the name of the "Lord"—which is joined to His pronoun (peace be upon him) in both places—there is an exaltation of the possessed and a nobility of the possessor that is not hidden. The explicit mention of the "sea" and the "words" in the place of the pronoun is for the sake of increased confirmation.

"Madadan" (as an addition) is in the accusative case as a specifier (tamyiz), as in the saying: "For love is enough for you, like it, in patience." Abu al-Fadl al-Razi permitted its being in the accusative as an infinitive (masdar), in the sense of: "If We had aided with the like of it an aiding," where madad acts in place of imdad, along the lines of what was said in His saying: "And Allah caused you to grow from the earth a growth." This, however, is forced.

Hamza, al-Kisa'i, Amr ibn Ubayd, al-A'mash, Talha, and Ibn Abi Layla read "qabla an yanfada" with a ya at the end of the letters. al-Sulami read "an tinfada" with a shadda, on the form of tafa''ala in the past tense, and it is reported likewise from 'Asim and Abu 'Amr; it is the intransitive (mutawa') of nafada (to exhaust), like kasartuhu fa-takassara (I broke it and it broke). al-A'raj read "bi-mithlihi midadan" with a kasra on the mim, as the plural of midda, which is that which a writer uses to draw ink and write with. Ibn Mas'ud, Ibn Abbas, Mujahid, al-A'mash (with a difference), al-Taymi, Ibn Muhaysin, Humayd, al-Hasan (in one narration), and Abu 'Amr—as well as Hafs—read it as "midadan" with an alif between the two dals and a kasra on the mim.

The cause of revelation is that Huyayy ibn Akhtab, as narrated by al-Tirmidhi from Ibn Abbas, said: "In your Book [it says]: 'Whoever is given wisdom has certainly been given much good,' then you recite: 'And you have not been given of knowledge except a little.'" His intent was to object that a contradiction occurred in your Book, based on the assumption that wisdom is knowledge, and that "much good" is the essence of wisdom, not its effects or what follows from it, because a single thing cannot be "little" and "much" at the same time. The verse is an answer to that, by instructing that "little" and "much" are relative matters. It is permissible for a thing to be much in itself while being little in relation to something else. For the sea, in its greatness and abundance—especially when its likes are added to it—is little in relation to the words of the Almighty.

It is also said that the cause of this was that the Jews said to the Messenger (peace be upon him): "How do you claim that you are the Prophet of all nations, sent to them, and that you have been given the knowledge that people need, when you were asked about the Spirit and did not answer concerning it?" Their intent was to object, claiming a contradiction between his claim (peace be upon him) and his state, as they alleged, based on the premise that knowledge of the reality of the Spirit is among what people need, and that he (peace be upon him) did not provide information about it, neither explicitly nor implicitly. The answer to this is the denial that knowledge of the reality of the Spirit is among what people need in the affairs of their religion, for which the prophets (peace be upon them) were sent. The one who says, "You are more knowledgeable about the affairs of your world," does not claim knowledge of what people need absolutely. You know that the verse would not be an answer to what was mentioned—assuming that was the cause of revelation—except by joining the subsequent verse to it, and even then, this requires a type of straining.