The psychological effect of every impression is such that each impression has a tendency to be held by the mind, all we see during the day, consciously or unconsciously, an influence upon our life. All good or bad things or things with beauty or ugliness, they remain with us and flourish in our minds. If it was an impression of beauty, that would flourish; if it was an impression of ugliness, that would flourish. This is the principal reason why dreams have effect upon our lives. It is the impression that the dream has made upon us which works out its destiny in the waking state. Therefore, if by being on one's guard, instead of resisting evil one would only slide it over, it would run away by its own force.