I need help in world religions. (Judaism)?

They all basically believed the same things but had been having fights. One thing that caused fighting was any kind of sin, such as intermarrying with the heathen, getting into heathen religions, and all the other usual things that go on such as adultery, fornication, stealing, , etc. They came together for the last years of David's reign when he became ruler of all of Israel, Judah included.