Oral transmission of the revelation was based on hifz or memorization and the Prophet Muhammad himself was the first to commit a revelation to memory after the Angel Gabriel had brought it to him:

'Move not thy tongue concerning the (Qur'an) to make haste therewith. It is for Us to collect it and promulgate it; but when We have promulgated it, follow thou its recital' (75: 16-19)

'... an apostle from God, rehearsing scriptures, kept pure and holy ...' (98: 2)

The Prophet then declared the revelation and instructed his Companions to memorise it. The case of Ibn Mas'ud, who was the first man to publicly recite the Qur'an in Makka, shows that even in the very early phase of the Islamic umma recital of the revelation from memory was practised by the Companions:

'... the first man to speak the Qur'an loudly in Makka after the apostle was 'Abdullah bin Mas'ud. The Prophet's Companions came together and mentioned that the Quraish had never heard the Qur'an distinctly read to them ... When (Ibn Mas'ud) arrived at the maqam, he read "In the name of God the Compassionate the Merciful", raising his voice as he did so. "The Compassionate who taught the Qur'an ..." (55:1) ... They got up and began to hit him in the face; but he continued to read so far as God willed that he should read ... [Guillaume, E.: The Life of Muhammad (abbr. as Ibn Hisham), London, 55, pp. 141-2; Ibn Hisham: Sira al-nabi, Cairo, n.d., 1, p.206.] It is also reported that Abu Bakr used to recite the Qur'an publicly in front of his house in Makka. [Sira Ibn Hisham, The Life of Muhammad]

There are numerous ahadith, giving account of various efforts made and measures taken by the Prophet to ensure that the revelation was preserved in the memory of his Com- panions. The following is perhaps the most clear:

'Narrated 'Uthman bin 'Affan: The Prophet said: "The most superior among you (Muslims) are those who learn the Qur'an and teach it".' [Bukhari, VI, No. 546.] It is also well known that the recital of the Qur'an during the daily prayers is required and hence many Companions heard repeatedly passages from the revelation, memorized them and used them in prayer.

The Prophet also listened to the recitation of the Qur'an by the Companions.

Narrated 'Abdullah (b. Mas'ud): 'Allah's Apostle said to me: "Recite (of the Qur'an) for me". I said: "Shall I recite it to you although it had been revealed to you?!" He said: "I like to hear (the Qur'an) from others". So I recited Surat-an-Nisa' till I reached: "How (will it be) then when We bring from each nation a witness and We bring you (O Muhammad) as a witness against these people?" ' (4:

41). 'Then he said: "Stop!" Behold, his eyes were shedding tears then.' [Bukhari, VI, No. 106.]

The Prophet sent teachers to communities in other places so that they might receive instruction in Islam and the Qur'an.

The case of Mus'ab bin 'Umair illustrates that this was so even before the hijra:

'When these men (of the first pledge of 'Aqaba) left (for Madina) the apostle sent with them Mus'ab bin 'Umair ... and instructed him to read the Qur'an to them and to teach them Islam and to give them instruction about religion. In Madina Musiab was called "the reader".' [Ibn Hisham, p. 199.] Another well-known case concerns Mu'adh bin Jabal who was sent to Yemen to instruct the people there.

Suyuti [Itqan 1, p. 124.] mentions more than twenty well-known persons who memorized the revelation, among them were Abu Bakr, 'Umar, 'Uthman, 'Ali, Ibn Mas'ud, Abu Huraira, 'Abdullah bin 'Abbas, 'Abdullah bin 'Amr bin al-'As, 'A'isha, Hafsa, and Umm Salama.

From among these, the Prophet himself recommended especially the following:

'Narrated Masruq: 'Abdullah bin 'Amr mentioned 'Abdullah bin Mas'ud and said: I shall ever love that man for I heard the Prophet saying: Take (learn) the Qur'an from four: 'Abdullah bin Mas'ud, Salim, Muiadh and Ubay bin Ka'b'. [Bukhari, VI, No. 521.] Another hadith informs us about those Companions who had memorized the Qur'an in its entirety and gone over it with the Prophet before his death:

'Narrated Qatada: I asked Anas bin Malik: Who collected the Qur'an at the time of the Prophet? He replied, Four, all of whom were from the Ansar: Ubay bin Ka'b, Mu'adh bin Jabal, Zaid bin Thabit and Aba Zaid.' [Bukhari, VI, No. 525.] The fact that some of the earliest historical reports make special mention in the accounts of the battles that were fought, of Muslims killed who knew (something of) the Qur'an by heart, gives a clear indication that memorization of the revelation was considered important and widely practised from the earliest times. [See below, on collection of the Qur'an in Abu Bakr's time.]

It is therefore certain that the Qur'an had been memorized by the Companions of the Prophet during his lifetime. This tradition continued among the Companions after the Prophet's death and, later, among the tabi'un and all generations of Muslims that have followed, until today.