Tafsir of Al-Isra 17:107

{Say, "Believe in it or do not believe."} This is a command to turn away from them, to hold them in contempt, and to disdain their status. It signifies that one should not care about them, their belief, or their refusal to believe.

If they—being people of ignorance and polytheism—do not enter into faith and do not believe in the Quran, then those who are better and superior to them—the scholars who have read the scriptures and understood what revelation and religious laws are—have indeed believed in it and affirmed it. It has been established for them that he is the Arab Prophet promised in their books. When it is recited to them, they fall upon their chins in prostration and glorify God, honoring His command and the fulfillment of what He promised in the revealed books, and the glad tidings He gave regarding the mission of Muhammad (peace be upon him) and the revelation of the Quran to him. This is what is meant by "the promise" in His saying: {Indeed, the promise of our Lord is always fulfilled.}

{And it increases them in humility} Meaning: The Quran increases them in the softening of the heart and the moistening of the eyes [with tears].

If you ask: What is the clause {Indeed, those who were given knowledge before it} justifying? I say: It may be a justification for His saying {Believe in it or do not believe}, or it may be a justification for the command {Say} as a means of consoling the Messenger of God (peace be upon him) and soothing his soul. It is as if it were said: "Find consolation for the disbelief of the ignorant in the belief of the scholars." According to the first interpretation: "If you do not believe in it, those who are better than you have indeed believed in it."

If you ask: What is the meaning of falling upon the chin? I say: It is falling upon the face. The chin—the junction of the two jaws—is mentioned because it is the first part of the face that meets the ground when one prostrates.

If you ask: The preposition of elevation (‘ala) is clear in meaning when one says "he fell upon (‘ala) his face or his chin," so what is the meaning of the lam (for) in "he fell for (li) his chin and his face"? I say: It means he made his chin and face the object of the falling, designating it for that purpose, for the lam denotes specification (ikhtisas).

If you ask: Why is "falling upon their chins" repeated? I say: Because of the difference between the two states: their falling while they are prostrating, and their falling while they are weeping.

{Say, "Call upon Allah or call upon the Most Merciful. Whichever [name] you call - to Him belong the best names." And do not recite [too] loudly in your prayer, nor recite too quietly, but seek between that an intermediate way.}