Re: The Prophet Kills 500 Jews?
Sa'ad bin Mu'adh was actually the head of the Ansaars (the helpers, who embraced the Prophet sas and his companions whole heartedly). Sa'ad probably became Muslim as soon as the Prophet first arrived in Madina.
It is narrated Sa'ad was injured in the battle. Apart from that Sa'ad bin Mu'adh being the head of a tribe, would most likely be a senior figure in the society...probably bit too old for the beheading 900 Jews.