Islam is unluckily the direct descendant of teh religious beliefs of those who are called Arabs or servants (for slaves) in the Bible, and then the strict rules against evil (root Bal for the devil) taht we find in Islam were those of the community of teh Zealots of the Dead Sea Scrolls led by James, the brother of Jesus. Islam is typically the ideology of a crushed down and dominated class of people.
Muhammad has only captured this power (class consciousness is always powerful) and directed it against those who dominated his society who were following other religions that we call pagan with the ease of people who do no understand mu;ch.