Aeon has an interesting article on the connection between dreams, visions, and spiritual movements which spring from visions:
https://aeon.co/essays/why-are-dreams-such-potent-vehicles-for-the-supernatural
Some notable points are that during REM sleep, the part of the brain associated with critical thinking is supressed while the part associated with emotions is active, and that what one does with a demonstration that spirituality is rooted in REM sleep is a personal choice. The article also notes that dreams may be responsible for the development of religous based terrorism and fanaticism.
