Ulum al Qur'an
The Qur'an Dictated by the Prophet
The Qur'an was not only written down by those Companions who did so on their own initiative. Indeed, the Prophet, when a revelation came, called for the scribe and dictated to him. The Prophet while in Madina had several such scribes, [M. M. A'zami, in his book Kuttab al-Nabi (Beirut, 1393/1974) mentions 48 persons who used to write for the Prophet.] among whom Zaid bin Thabit was very prominent.
Narrated al-Bara': There was revealed 'Not equal are those believers who sit (at home) and those who strive and fight in the cause of Allah' (4: 95). The Prophet said: 'Call Zaid for me and let him bring the board, the ink pot and the scapula bone (or the scapula bone and the ink pot).' Then he said: 'Write: Not equal are those believers ...
[Bukhari, VI, No. 512; also VI, No. 116-18.]It is also reported that material upon which the revelation had been written down was kept in the house of the Prophet. [Suyuti, Itqan, I, p. 58.]