Thereupon...
Thereupon, they would write the verses preceding and following that verse and leave a vacant place for it until that person returned or was sent for."7 It is narrated from Ubayy ibn Kaab that: "They collected the Qur'an in masahif during the caliphate of Abu Bakr, may God have mercy on him. Men used to write on being dictated by Ubayy, and when they reached the verse of the Surat al-Baraah, ثم انصرفوا صرف الله.. (9:127) they thought that it was the last verse of the Qur'an to be revealed.
Thereupon Ubayy ibn Ka`b said: 'After this, two more verses have been read to me: لقد جاءكم رسول "8 Abü Dawud ibn al-Zubayr narrates that Abu Bakr said to `Umar and Zayd: "Sit at the door of the mosque and whoever comes to you with two witnesses evidencing anything from the Book of Allah, write it "9 Ibn Sirin reports that both Abu Bakr and `Umar died without the Qur'an having been collected)10 .
Ibn Sa`d reports that `Umar was the first person to collect the Qur'an11 Similar traditions are present in a large number in the Sihah and other works, and to accept what they say about the Qur'an implies negating the tawatur of the Qur'an and accepting it as based on akhbar ahad, such as the story about incorporation of verses on the sole authority of Khuzaymah, or on the evidencing of two witnesses, or on the narration of Ubayy ibn Ka`b, or on the word of a person who happened to be out in the desert and who had to be called to recite to them.
Some traditions - like the one about a verse which was with a qari martyred in Yamamah - cast doubt on the completeness of the Qur'an. Apart from this, other questionable issues crop up which a person cannot disregard were he to accept the traditions of the Sihah in this regard. Al-Zarkashi was aware of this, and he has mentioned an alternative interpretation in this regard which cannot possibly be accepted.
He says regarding the observation of Zayd concerning the acceptance of two verses from Khuzaymah: It does not imply that a Quranic text has been proved by khabar al-wahid because Zayd, and similarly the other , had assuredly heard it and knew its place in the .Suat al-'Ahzab on the basis of the Prophet's instruction. Then Zayd had forgotten it, and on having heard it again recollected it.