It is narrated from Khalifah bin Khayyat that: Mujashi' bin Mas'ud bin Tha'labah bin Wahb bin A'idh bin Rabi'ah; his kunyah was Abu Sulayman. The mother of him and of his brother Mujalid was Mulaykah bint Sufyan bin al-Harith bin Asad bin Khuzaymah. Mujashi' was martyred on the day of the Lesser Battle of the Camel in the year 36 AH, and was buried in his house among Banu Sulaym near Banu Sadus. He had more than one house in Basrah, one of which was near the Jami' Mosque.

It is narrated from Sayyiduna Mujashi' bin Mas'ud (may Allah be pleased with him) that he said: After the Conquest of Makkah, I brought my brother Mujalid to the Messenger of Allah (peace and blessings be upon him) and said: "O Messenger of Allah! I have brought my brother Mujalid to you so that you may take his pledge of allegiance for hijrah." He (peace and blessings be upon him) said: "The people of hijrah have gone away with its merit." I said: "Then, O Messenger of Allah, on what will you take his pledge?" He (peace and blessings be upon him) said: "I take his pledge on Islam, faith and jihad."