It is narrated from Muhammad bin Umar (al-Waqidi) that the name of Abu al-Yasar (may Allah be pleased with him) is Ka'b bin Amr bin Abbad bin Amr bin Sawad. According to all the reports, he took part in the Pledge of al-Aqabah. At the time of the Battle of Badr he was twenty years old, and he took part in the Battles of Uhud and the Trench (Khandaq) and in all the campaigns with the Messenger of Allah (peace and blessings be upon him). He was a short, stocky man with a large belly. He passed away in the year 55 AH in Madinah.