Do you think it is possible that all the people how had memorized the Quran,
by heart, would
all make the same mistake and
all forget the same verse, or that they would
ALL think it was something different?! And not only that but if they thought it was something differnet, they would have all had to think it was the same different thing!
The Quran was not based on the memory of one Muslim, but many, many Muslims! In fact, so many that it would be impossible that these people would have all agreed on a lie!
Oh, and also, the Quran was written down at the time of the prophet, but just NOT in the form of one complete book.
This here explains a little about how the Quran was complied:
It is not possible for a Muslim to entertain doubts concerning the immutability of the Qur’aan, because Allaah has guaranteed to preserve the Qur’aan. Allaah says (interpretation of the meaning):
“Verily, We, it is We Who have sent down the Dhikr (i.e. the Qur’aan) and surely, We will guard it (from corruption)”
[al-Hijr 15:9]
The Qur’aan was preserved in the hearts of the Sahaabah who had memorized it, and on the trunks of trees and thin white stones until the time of the caliph Abu Bakr al-Siddeeq (may Allaah be pleased with him)*. During the Riddah wars many of the Sahaabah who had memorized the Qur’aan were killed, so Abu Bakr (may Allaah be pleased with him) was afraid that the Qur’aan may be lost. He consulted the senior Sahaabah concerning the idea of compiling the entire Qur’aan in one book so that it would be preserved and would not be lost, and this task was entrusted to the great hafiz** Zayd ibn Thaabit and others who had written down the Revelation. Al-Bukhaari narrated in his Saheeh that Zayd ibn Thaabit (may Allaah be pleased with him) said:
“Abu Bakr As-Siddeeq sent for me when the people of Yamamah had been killed (i.e., a number of the Prophet's Companions who fought against Musaylimah). (I went to him) and found 'Umar bin al-Khattaab sitting with him. Abu Bakr (may Allaah be pleased with him) said (to me), ‘ ‘Umar has come to me and said: “Casualties were heavy among the Qurra' of the Qur'aan (i.e. those who knew the Qur’aan by heart) at the Battle of Yamaamah, and I am afraid that more heavy casualties may take place among the Qurra' on other battlefields, whereby a large part of the Qur'an may be lost. Therefore I suggest that you [Abu Bakr] should issue orders that the Qur’aan be collected.” I said to 'Umar, “How can you do something that the Messenger of Allaah (peace and blessings of Allaah be upon him) did not do?" 'Umar said, “By Allah, this is something good.” ‘Umar kept on urging me (to accept his proposal) until Allah opened my heart to it and I began to realize the good in the idea which 'Umar had realized.’ Then Abu Bakr said (to me): ‘You are a wise young man and we have a great deal of confidence in you. You used to write down the Revelation for the Messenger of Allaah (peace and blessings of Allaah be upon him). So you should seek out the Qur’aan [i.e., the fragments on which it is written] and collect it (in one book).’ By Allaah, if they had ordered me to move one of the mountains, it would not have been harder for me than this command to collect the Qur’aan. I said (to Abu Bakr), ‘How can you do something which the Messenger of Allaah (peace and blessings of Allaah be upon him) did not do?’ Abu Bakr said, ‘By Allaah, it is a good thing.’ Abu Bakr kept on urging me (to accept his proposal) until Allah opened my heart to it as He had opened the hearts of Abu Bakr and ‘Umar. So I started to look for the Qur’aan and collected it from (the fragments on which it was written of) palm-stalks, thin white stones and the hearts of men (i.e., from men who knew it by heart), until I found the last verse of Soorat al-Tawbah with Abu Khuzaymah al-Ansaari, and I did not find it with anybody other than him. The verse is :
‘Verily, there has come unto you a Messenger from amongst yourselves. It grieves him that you should receive any injury or difficulty…’
[al-Tawbah 9:128 – interpretation of the meaning]
… until the end of Soorat Baraa’ah (Soorat al-Tawbah).
These fragments remained with Abu Bakr until he died, then with ‘Umar for the rest of his life, then with Hafsah bint ‘Umar (may Allaah be pleased with them both).”
http://islamqa.com/index.php?ref=23487&ln=eng
*I would like to add that the "time of Abu bakr" was directly after the death of the prophet (no room for 'generations' to change anything.
** A Hafiz is someone who has memorized the whole Quran by heart.
So, what do you think?