From the earliest times, the Messenger of Allah (saw) had the wahy scribes dictate the incoming verses and specifically checked whether what was written was recorded correctly. He also informed His scribes how and in which surah the verses would be placed. Verse 5 of the Surah al-Furqan clearly reveals that the Qur'an was written from the earliest times: “And they say: "Legends of the former peoples which he has written down, a And they are dictated to him morning and afternoon." (Furqan, 25/5)

After the death of the Prophet Muhammad (saw), the parts on which the revelation was written were collected and meticulously compiled into a book by  Zayd ibn Thabit, who was commissioned by the first caliph, Abu Bakr. Of course, his assignment to this job was not in vain. Because besides being a Qur'an hafiz (memorizer), he was a reliable, young, dynamic and intelligent person. Abu Bakr also ordered Zayd ibn Thabit to ask for written evidence from two persons for each verse. Again, he declared that anyone who has written parts of the Qur'an should give them to Zayd ibn Thabit.  

The Qur'an was reproduced with the same meticulousness by a commission formed during the reign of Caliph Uthman. This commission consisted of four people  and Zayd ibn Thabit was its chairman. Rumors state that the written Qur'anic texts were read in the al-Masjid an-Nabawi, checked and then sent to various centers. 

The Qur'an has been preserved in its entirety over the centuries, both by writing and memorizing. As a matter of fact, the following verses clearly show that the Qur'an is under the protection of Allah (swt): 

"Indeed, it is We who sent down the Qur'an and indeed, We will be its guardian." (Hijr, 15/9)

The Qur'an has made the following call to all its opponents who deny it: “Say, "If mankind and the jinn gathered in order to produce the like of this Qur'an, they could not produce the like of it, even if they were to each other assistants."(Isra, 17/88) As seen here, the Qur'an literally challenges those who claim that it is not a Divine Book. It calls upon them not to hold back and to do everything they can. It is not possible for an ordinary person who has not been interested in poetry in his life to dare to take such a challenge. Because he knows that the Arabs were very successful in literature and poetry. History makes this clear.

Again, it is possible to underline the following points about the Qur'an being a Divine Book: