I'll leave the sources up to other people, but the general idea is that the more dualistic parts of later Jewish theology might have originated with Zoroastrian

I'll leave the sources up to other people, but the general idea is that the more dualistic parts of later Jewish theology might have originated with Zoroastrianism. Heaven, hell and the devil as God's antagonist supposedly weren't part of the story originally: the devil used to be an angel with a job description that placed him in opposition to humanity, but not God, and everyone went to Sheol after death.