It is narrated from Mus'ab bin Abdullah that Mus'ab al-Khayr is the son of Umayr bin Ubayd bin Hashim bin Abd Manaf bin Abd al-Dar bin Qusayy. He is the Qur'an teacher whom the Messenger of Allah (peace and blessings be upon him) sent, before his (peace and blessings be upon him) arrival in Madinah, to teach the people of Madinah the Qur'an. Many people accepted faith at his hands, and he also took part in the Battle of Badr.