In the seventh century, before Muhammad became the prophet and invented Islam he was a spice trader, and as such he traveled the route to Syria many times, by way of Palestine. His contacts with Judaism from Yathrib to Damascus must have been powerful. Interaction with the Jews would later influence the formation of Islam.
His observations had such an effect that Islam mirrors many of the same rituals as Judaism. That’s why today, Halal is similar to Kosher, Muslims keep their heads covered in reverence to Allah, and males are circumcised at birth. Many of these customs come right from Muhammad’s Jewish influence before he became the Prophet Muhammad in 622CE.
By 620 Muhammad had a fairly large following and had already by that time had established many of the precepts for Islam. He wanted desperately the endorsement of the Jews whose ritual and observance he admired so much. The Bani Kuriza, the Jewish tribe in Yathrib, rejected Muhammad’s call to recognize his prophetic license.
There’s some literature that suggests they even ridiculed him for the suggestion. Not out of the realm of possibilities, Jewish history is replete with false messiahs coming and demanding Jewish allegiance, Muhammad in Jewish history is part of a long line of these people