In later times the written Qur'an became the main source of Islamic learning. But one danger was still lurking. In sacred books even very minor differences can become a source of great controversy. It was feared that if people wrote the Qur'an on their own, differences in transcribing (kitabat) e.g. writing 'eether' for 'either' and in recitation would create widespread dissension and there would be no way of putting an end to it. For instance, just one word in the first chapter of the Qur'an was written in different ways according to the pronunciation of different dialects: maalik-e-yaumuddin, malik-e-yaumuddin and maleek-e-yaumuddin, etc.; with the passing of time and changes in the style of writing, the differences in the manuscript would have become a source of great contention. Therefore, on the advice of Umar, Abu Bakr decided to have an authentic copy of the Qur'an prepared under state patronage and thus put an end forever to the possibility of phonetic differences obscuring the true meaning of the text.

For this purpose Zayd ibn Thabit was the most competent, as he was the katib of the Prophet. Zayd and Ubayy ibn Kaab both had joined in the 'last recitation' having heard the Qur'an directly from the Prophet in the order still extant today. Not only had they memorised the entire Qur'an, but they also possessed the whole text in written form. The first caliph commanded them to collect all the available parts of the scriptures and to compile them. (Bukhari). After this decision had been taken, Umar made an announcement in the Mosque that whoever had any piece of writing from the Qur'an should bring it and hand it over to Zayd.

During the first caliphate, the Qur'an not only existed in written form on the bark of date palms, stones, leather, etc, but was also preserved in the memory of the companions. The Qur'an, when made into a book, was arranged in the order memorized by the companions, and the verses have been preserved in that same order right up to the present day.

Zayd ibn Thabit's work was more a process of collection than of compilation. That is, the scattered bits and pieces of the Qur'an in written form were collected by him, not just to be assembled and bound in one volume, but to be used to verify the authenticity of the Qur'an as memorised and passed on in oral tradition by countless individuals. Once this exact correspondence between the oral and written forms of the Qur'an had been established beyond any reasonable doubt, Zayd proceeded to put the verses of the Qur'an down on paper in their correct order.

Harith Muhasibi writes in his book, Fahm As-Sunan, that the transcription of the Qur'an was nothing new, because the Prophet himself had arranged for it to be written down. But it was written separately on Riqa'a, Likhaf, Katf, 'Asib, etc. All the materials on which the Qur'an was written were available in the Prophet's house, but had not been put in any special order. What the collector did was assemble all these parts and then bind them together so that no part was destroyed. (Al, Itqan, v. 1, p. 40)

This elaborate arrangement of the Qur'an was made so that there should not be even the minutest discrepancy vis-à-vis the original revelation. If this extraordinary care had not been taken, differences would have resulted from the slightest lapse in memorising and transcription. For instance, when Umar recited this verse to Zayd ibn Thabit, "As for those who led the way, the first of the muhajirs and the Ansar, those who nobly followed them," Zayd said, that he remembered this verse with waw, that is, with 'and' after Ansar. So the investigation started, and finally the other memorisers of the Qur'an came and confirmed that the opinion of Zayd was right. So in the volume the verse was written with the addition of 'and'.

In former times, when the accepted way of disseminating the subject matter of a book was to memorise it, then recite it, it was quite exceptional that the Qur'an should have been preserved in writing as well as memorised. This was like having a 'double checking' system, whereby memory plus written words and written words plus memory could be constantly compared for verification.

After Zayd ibn Thabit had prepared the entire Qur'an and bound it in the form of a book, all other materials collected from different companions, for the purpose of checking and rechecking, were all burnt. Now this volume was handed over to the caliph. After Abu Bakr's death it remained with Umar, the second caliph. After the death of Caliph Umar it remained in the custody of Hafsa, daughter of Umar and wife of the Prophet.