Tafsir of Al-Waqi'ah 56:77

It is a glorification of the oath, establishing and confirming it. His saying—Exalted is He—(If you only knew) is a parenthetical phrase placed between the adjective and the noun it describes, serving as an emphasis for that glorification.

The response to "If" is either omitted, intending to negate their knowledge, or omitted due to confidence in its clarity; meaning: "had you known, you would have revered it," or "you would have acted according to its requirements." The reason for the greatness of that oath has already been indicated in what preceded, or it is manifest based on the interpretation of "the positions of the stars" according to what has been narrated from Ibn Abbas and the group.

The meaning of the Qur'an being "noble" (karim) is that it is excellent and pleasing in its kind among the books, or beneficial and possessing abundant benefits. How could it be otherwise, when it encompasses the foundations of the sciences essential for the reform of worldly life and the afterlife? Nobility (karam) in this context is metaphorical, as Al-Tibi stated, derived from "generosity" (karam) in its common sense. It is also said that nobility is more general than mere abundance of giving and benevolence; it includes being characterized by praiseworthy traits, such as abundant benefit, for that is a praiseworthy description. Thus, its being [a noble book] is literal. It is also permissible that it means "noble in the sight of Allah, the Exalted," though it is said that this returns to the previous interpretation and involves unnecessary estimation. Regardless, the focus of the benefit is the aforementioned description.

It is said that the referent of the pronoun is the Qur'an, not merely by the title of it being a "Qur'an"—whereby the information given about it would merely be that it exists—but rather the benefit is that it is "read" (maqru') to the Prophet, peace and blessings be upon him, and not that he originated it, as the disbelievers claimed.