Sahih Bukhari | Volume 6 | Hadith Number 511

Narrated by Zaid bin Thabit
Abu Bakr sent for me and said, "You used to write the Divine Revelations for Allah's

Apostle

'Verily there has come unto you an Apostle (Muhammad) from amongst yourselves. It grieves him that you should receive any injury or difficulty...' (9:128-129)