Narrated Az-Zuhri

"From 'Ubaid bin As-Sabbaq, that Zaid bin Thabit narrated to him, he said: 'Abu Bakr As-Siddiq sent for me - (regarding) those killed at Al-Yamamah - and 'Umar bin Al-Khattab was with him. He (Abu Bakr) said: "'Umar came to me and said: The fighting inflicted many casualties among the reciters of the Qur'an on the Day of Al-Yamamah, and I fear that there will be more casualties among the reciters in other parts of the land, such that much of the Qur'an may be lost. In my view, you should order that the Qur'an be collected.'" Abu Bakr said to 'Umar: "How can I do something which was not done my the Messenger of Allah (ﷺ)?" 'Umar said: 'By Allah! It is something good.' 'Umar continued trying to convince me until Allah opened up my chest to that which He had opened the chest of 'Umar, and I saw it as he saw it." Zaid said: 'Abu Bakr said: "You are a young wise man, and we have no suspicions of you. You used to write down the Revelation for the Messenger of Allah (ﷺ) as the Qur'an was revealed." He (Zaid) said: 'By Allah! If they had ordered to move one of the mountains it would have been lighter on me than that.' He said: 'I said: "How will you do something which was not done by the Messenger of Allah (ﷺ)?" Abu Bakr said: "By Allah! It is something good." Abu Bakr and 'Umar continued trying to convince me, until Allah opened up my chest for that, just as He had opened their chests, the chest of Abu Bakr and the chest of 'Umar. So I began searching for Qur'anic material from parchments, leaf stalks of date-palms and Al-Likhaf - meaning stones - and the chests of men. I found the end of Surah Bara'ah with Khuzaimah bin Thabit: Verily, there has come to you a Messenger from among yourselves. It grieves him that you should receive any injury or difficulty. He is eager for you; for the believers (he is) full of pity, kind, and merciful. But if they turn away, say: "Allah is sufficient for me. There is no god but He, in Him I put my trust, and He is the Lord of the Mighty Throne (9:128 & 129).'"