A'isha
Miss Schoolteacher
How did this come about? AFAIU Christianity was quite prominent in the regions of Muhammed's early conversions and Christians appear to have influenced him. Is there a direct source of the more Jewish elements (law-keeping, rituals, etc)? Or is it likely to be a more reactionary development, i.e. that Christians were corrupting the law and that the return to the "true" revelation meant going back to something more Jewish?
Judaism was a bigger influence due to having large, organized communities in the Arabian peninsula. Christianity was present, but more scattered and incoherent, consisting of a number of smaller sects and sub-sects that were generally persecuted by the Byzantines (the Christianity as described in the Qur'an is noticeably different in a number of core details from the Christianity we know today).