Zoroastrian theology is strongly dualistic.
In his visions, Zarathustra was taken up to heaven, where Ahura Mazda revealed that he had an opponent, Aura Mainyu, the spirit and promoter of evil. Consequently, Zoroastrianism is a highly ethical religion. Zarathustra taught that humans are free to choose between right and wrong, truth and lie, and light and dark, and that their acts, words, and thoughts would affect their lives after death. His ideas of heaven, hell, and the resurrection of the body profoundly influenced Judaism, Christianity, and Islam. Later Zoroastrianism conceived of an opposition between body and soul, though there was no suggestion in its theology that the body was evil and the soul was good.