Isaiah 29:12

The Prophet Muḥammad used to speak the revelation, memorizing it by heart, from his lips without reading, because he was unlettered, unable to read or write. In the Book of Isaiah, there is a prophecy about Muḥammad that one of his attributes is that he does not know how to read or write. The text of the glad tiding is:

12. “And the book is delivered to him that is not learned, saying, Read this, I pray thee: and he saith, I cannot read.” (Isaiah 29:12) This phrase matches the saying of the Prophet Muḥammad to the angel Gabriel when he descended upon him in the cave of Ḥirā’ and said, “Read!” He replied, “I am not a reader,” meaning “I do not know how to read.” [Al-Bukhari] For benefit; Allāh the Almighty has said to His Prophet Muḥammad in the Qur’ān: “And you did not recite before it any scripture, nor did you inscribe one with your right hand. Otherwise, the falsifiers would have had [cause for] doubt. Rather, the Qur’ān is distinct verses [preserved] within the breasts of those who have been given knowledge. And none reject Our verses except the wrongdoers.” [Al-‘Ankabūt (The Spider), 29:48-49]. The meaning of the noble verse: You, O Messenger, did not read a book before, nor did you write letters with your right hand before the Qur’ān was revealed to you. Rather, We made you unlettered, neither reading nor writing. In addition, the wisdom in that is that if you had read or written, people would have said: You authored this book (i.e., the Qur’ān), or you read the previous books and copied from them and made this Qur’ān. But when We made you unlettered, neither reading nor writing, then people heard this Qur’ān from you, and they know that humans cannot produce it, nor a verse of it, and that it does not resemble the speech of humans; this doubt was severed from them, and they knew that there was no alternative but to say that it is a revelation from Allāh. So whoever believed in your prophethood believed, and whoever was arrogant was arrogant. *** 90