If you want to know where the hostilities between Jews and Muslims began, it started during the time of Mohammed. Medina was originally a town called Yathrib founded by three Jewish Arab tribes. When Mo fled Mecca a half step ahead of the assasin's dagger, he did so partly on the word of the Rabbis of Yathrib that they would be allies in any attacks that the Meccans would attempt. Rabbis at first thought Mohammed might be a Jewish prophet. Then when they saw him first hand, they realized they were mistaken and reneged on their oaths. Which put the Moester in a bit of a fix, to say the least. So two tribes were expelled. Then during a climatic battle with the Meccans (Battle of the Trench) the last tribe were caught conspiring with the Meccans. As a consequence, Mohammed ordered some 600 adult Jewish males beheaded right in the center of town

*In this case, he is heading for a fortress called Khaybar on the border of the Arabian desert where the Jewish Arab tribes from Medina took refuge. In this case, there was no massacre, but the Muzzies did lay down an ominous warning to get the Farouq out of Arabia