Commentary on al-Jalal al-Bayn's Tafsir: “The sending down of the Book” — the Qur'an is the subject (mubtada'), “from Allah” is its predicate (khabar), “the Mighty” in His dominion, “the All-Knowing” regarding His creation.

Then Allah, Mighty and Majestic, said: "

The revelation of the Book

تنزيل الكتاب

the Qur'an " meaning that the Book referred to here is the Qur'an, even though “the Book” is a generic term that could include the generic article (al) to encompass every book, but the apparent view is what the author adopted, because the intent is to establish that this Qur'an, which was sent down to the deniers, is from Allah, Mighty and Majestic.
And his statement: " mubtada' " means his saying: that it is a mubtada', and a mubtada' requires a khabar, and the khabar is his saying: For this reason, the commentator said: "

from Allah

من الله

its khabar " The sending down of the Book is from Allah, not from anyone else.
He said: " in His dominion

the Knowing

العليم

regarding His creation " The Mighty is the One possessing might. It has been mentioned previously that the might of Allah is divided into three categories: the might of divine decree, the might of overpowering, and the might of being free from deficiency. It is the same in every place where “the Mighty” appears; this is its meaning, namely that He is the One possessing might, and might has three categories: the might of divine decree, the might of overpowering, and the might of being free from deficiency. As for the might of divine decree, its meaning is that He is the One possessing honor and sovereignty. As for the might of overpowering, its meaning is that He is the One possessing dominance and authority. As for the might of being free from deficiency, its meaning is that He is free from every shortcoming and defect. The evidence for these three meanings and the explanation of their derivation have been presented previously. Therefore, the author's statement: "

the Mighty

العزيز

in His dominion " is deficient because he limited it to the meaning of the One who overpowers only, and the correct view is what we have mentioned to you.
He said: " regarding His creation " And the All-Knowing means the One possessing knowledge. The knowledge of Allah, Glorified and Exalted is He, is not limited, neither in beginning nor in end nor in quantity. The knowledge of Allah the Exalted is vast and comprehensive of everything. The knowledge of Allah the Exalted is eternal, meaning ignorance did not precede it. The knowledge of Allah the Exalted is everlasting, meaning forgetfulness does not overtake it. Thus, the knowledge of Allah the Exalted is vast and comprehensive in time and in manner; in time, meaning in the future and in the past, and in manner, meaning it encompasses everything that is subject to being known.