"[6] Muhammad bin Maslama volunteered and was aided by several others, including Ka‘b’s foster brother, Abu Na'ila.
The writings of the later commentators such as al-Zamakhshari, al-Tabarsi, al-Razi, al-Baydawi, and al-Asqalani provide another distinct report according to which Ka'b was killed because Gabriel had informed Muhammad about a treaty signed by himself and Abu Sufyan creating an alliance between the Quraysh and forty Jews against Muhammad during Ka'b's visit to Mecca.
[9]: 66 [10] According to Uri Rubin, some allusions to the existence of an anti-Muslim treaty between Quraysh and Ibn al-Ashraf may be found in the earlier sources.
[9]: 65–71 On some accounts, Huyayy bin Akhtab of Banu Nadir tribe had earlier refused to pay blood money for the murder of two Muslims and Abd-Allah ibn Ubayy had planned along with allied nomads to attack Muhammad.
The tribe at first decided to comply, but certain people from Medina who were not believers offered to help Banu al-Nadir fight the Muslims.