No surprise. The official Muslim position is that the Qur'an is divinely inspired, that it was revealed to Muhammad bit by bit, and that the words of the Qur'an are literlaly god's word.

There were many Jews and Christian tribes scattered across Arabia. Muhammad was very familiar with both religions, and there is a huge amount of borrowing.

Basically, Judaism grew out of various polytheistic cults into one specific monotheistic variant. Jesus "forked" Christianity into a new branch with many of the same teachings, and Muhammad did the same thing again, borrowing directly from both Judaism and Christianity.