29:48
And thou wast not (able) to recite a Book before this (Book came), nor art thou (able) to transcribe it with thy right hand: In that case, indeed, would the talkers of vanities have doubted.
Islamic tradition emphasizes that prior to the revelation of the Qurʾān, the Prophet Muhammad was not known to read or write and was therefore described as ummī (unlettered). Commentators explain that this characteristic served as evidence supporting the authenticity of the Qurʾānic revelation. If the Prophet had been literate, critics might have claimed that the message he conveyed was derived from earlier scriptures such as the Torah or the Gospel rather than from divine revelation. His lack of formal literacy is therefore understood by many scholars as a sign reinforcing the miraculous nature of the Qurʾān. For approximately forty years before the beginning of revelation, the people of Makkah had known him in this state, and he had no documented interaction with communities of the People of the Book from whom he might have acquired scriptural knowledge. When revelation began at the age of forty, the discourse attributed to him was regarded by believers as extraordinary both in its content and its eloquence.
Some later scholars have suggested that although the Prophet may initially have been unlettered, God could have granted him the ability to read or write at a later stage. In support of this interpretation, they refer to reports concerning the Treaty of Ḥudaybiyyah. According to these narrations, the written agreement between the Prophet and the leaders of Makkah initially included the phrase “Muhammad, the servant of God and His Messenger.” The Makkan representatives objected to the title “Messenger of God,” arguing that accepting this designation would have ended the dispute. The agreement was being written by ʿAlī ibn Abī Ṭālib, and when the Prophet requested that the phrase be removed, ʿAlī reportedly hesitated out of respect. Some narrations then state that the Prophet himself erased the disputed phrase and replaced it with “Muhammad, son of ʿAbd Allāh.”
Commentators, however, note that attributing the act of writing to the Prophet in such reports may reflect a common linguistic convention in which a document is associated with the person who orders or oversees its writing rather than the individual who physically writes it. Another interpretation suggests that if the Prophet wrote the phrase himself, it could have been a miraculous occurrence granted on that specific occasion. In either case, scholars often emphasize that writing a few words does not necessarily indicate full literacy. Within traditional Islamic interpretation, the Prophet’s description as ummī is considered a distinctive feature that underscores the divine origin of the Qurʾānic message rather than diminishing his status.
References:
Shafi, Muhammad (2008). Maariful Quran. (Vol .6 surah 29 verse 48).