Discernment of dreams
According to St John Climacus, a simple method exists of discerning the origins of dreams we can have – that is, where they come from. The method is as follows: “If we wake up from sleep peaceful this shows that we have been comforted by the angels unawares. If, on the other hand, we wake up troubled, we are suffering as a result of evil dreams and visions. A dream’s origin is indicated by whether it disturbs us or brings peace” (Met. Hierotheos. 2010. The science of spiritual medicine, p. 184).
Dreams from the Devil or demon-minions
Meanwhile, according to Diadochos of Photiki, dreams that originate from the Devil or demon-minions “do not keep the same shape, but change from one form to another, alarm the senses, resound with laughter or suddenly become threatening. The figures that appear . . . shout and menace, transform themselves into soldiers and sometimes screech at the soul” (ibid.). These dreams are characterized by color and change; they bring despair, which is always a sign of demonic deception.
Dreams from God
Dreams that originate with God “do not . . . [generally] change shape or provoke fear and horror, but bring inexpressible joy and gladness . . . [These dreams are unchanging, with no or minimal color; they lead to] “intense prayer, repentance and a willingness to change” (ibid.).