("Umar bn Al-Khattab) - Narrated Zaid bin Thabit Al-Ansari: Abu Bakr sent for me after the (heavy) casualties among the warriors (of the battle) of Yamama (where a great number of Qurra were killed).
'Umar was present with Abu Bakr who said. 'Umar has come to me and said, The people have suffered heavy casualties on the day of (the battle of Yamama, and I am afraid that there will be more casualties among the Qurra' (those who know the Qur'an by heart) at other battle-fields. whereby a large part of the Qur'an may be lost. unless you collect it. And I am of the opinion that you should collect the Qur'an. "You are a wise young man and we do not suspect you (of telling lies or of forgetfulness): and you used to write the Divine Inspiration for Allah's Messenger. Therefore. look for the Qur'an and collect it (in one manuscript).