Tafsir of Sad 38:29

(A Book): This is the predicate of a deleted subject, meaning it is the Quran or the Surah. It is permissible, based on the latter, to estimate it as masculine—i.e., "It is" or "This is"—which is preferred when considering the predicate. Estimating it as feminine is also permissible in consideration of the referent.

His saying, Exalted is He, (We have revealed it unto you) is its description.

His saying, Glorified be He, (blessed)—meaning possessing abundant religious and worldly benefits—is a second predicate for the subject, or a description of "(A Book)" for those who permit the explicit description to be delayed after the implicit one. It has been recited as (mubārakan) in the accusative case as a state (ḥāl) from the object of "We have revealed." It is a necessary state because blessing never departs from it—may Allah, Exalted be He, include us in its blessings and benefit us with its noble verses.

His saying, Mighty and Majestic is He, (that they may ponder its verses): This is connected to "We have revealed it." It is also considered possible that it is connected to a deleted element indicated by the text. Its original form is li-yatadabbarū (that they may ponder) with a tā’ after the yā’ (the final letter of the prefix). Ali—may Allah, Exalted be His Countenance, honor him—recited it according to this original form, meaning: We revealed it so that they may contemplate its verses, among which are these verses that explicate the secrets of creation and legislation, so that they may understand what is intended and follow their manifest superior meanings and appropriate interpretations. The subject pronoun (of the verb) refers to "those of understanding" due to dispute and the acting of the second (verb), or to the believers exclusively, or to both them and the corrupters.

Abu Ja‘far recited it as (li-tadabbarū) with a tā’ of address and a light dāl. The same is reported from ‘Asim and al-Kisa’i, with conflicting reports from them. The original form is li-tatadabbarū with two tā’s; one was deleted, based on the disagreement regarding whether it is the tā’ of the imperfect tense or the tā’ that follows it. The address is to the Prophet (may Allah bless him and grant him peace) and the scholars of his nation by way of generalization—meaning: that you and the scholars of your nation may ponder.

(And that those of understanding may remember):

That is, that those possessing minds purified and cleansed of impurities may take heed by it; or that they may bring to mind that which is as if embedded in their minds due to the excessiveness of their ability to know it through the evidences established for it. For the sending of messengers and the revealing of books are to clarify what cannot be known except through the way of religious law—such as the obligation of the five prayers—and to provide guidance toward that which the intellect is capable of grasping on its own, such as the existence of the Eternal Creator—His Majesty be glorified and His bounty be universal.