People generally translate the word 'Ummi' as the one who can neither read nor write, and which gives the impression that Muhammad (peace on him) was illiterate and remained so until the end of his life.
In 29:47, it is mentioned that “thus we have sent down the book to you…"
In 29:48, "Neither did you read any book before it, nor did you write any with your right hand…”
The words ‘before it’ mean that Muhammad (peace on him) did not read or write before the revelation, the way the Jewish and Christian religious men could. This implies that after the revelation, he could read and write well!
Other meanings of ‘Ummi’ also need to be considered.
In 2:78, the word ‘Ummiyyoon’ has been explained as “people who know not the Book’.
In 3:20 and 3:75, the word ‘Ummiyyeen’ is used in contrast to ‘those who were given the scripture’. Also see 62:2.
Now, 'Ummi’ not only means ‘one who cannot read and write’ but also means ‘one who does not have the knowledge of the scripture’ and ‘one who is not among those who were given the scripture’.
Hence, Muhammad (peace on him), before the revelation, neither had knowledge of the scripture (as a learned man would) nor he was among those who were given the scripture (not from the Jews or the Christians). While it is true that he was not a totally literate man who could not read or write before the Qur'an was revealed, afterwards he could do both.
The very mention of ‘IQRA’ (read) ‘ALLAMA’ and ‘QALAM’ (pen) in the very first revelation (96:1-5) place great emphasis on the Messenger to learn to read and write. Hence, he could not have turned a blind eye to a matter of such significance—after all he was going to be dictated by Allah to put in writing the entire Qur'an.
Remember, that the Messenger (peace on him) travelled far and wide as a caravan leader (successful businessman). Anyone who disputes the above assertions may reread the Quran very carefully because the unbelievers are shown accusing the Messenger for 'having written the Book with his own hands'.
The verses in question do not say that the messenger of Allah could NOT or did NOT read a book beforehand but that he did NOT read a revealed Scripture before the Qur'an.
The Ahadith that show some scribes writing whatever they felt (deliberately introducing errors in the Qur’an) while the Messenger approved it all, are forgeries.
How is it possible that the Lord of the visible and invisible worlds would allow such a thing to occur? In short, the Messenger of Allah had to write it all down in his own hand (in addition to memorizing it or having others copy it).
Pity the poor illiterate mullahs who think the Messenger of Allah (peace on him) was just like them. It is through such perversion of religion that men have come to believe that blowing themselves up and others with bombs is the Allah’s Way (sunnah Allah).
“And they say: ‘Tales of the ancients, which he has got them written down: and they are dictated before him morning and evening.’” (25:5)