Most dreams with fear, where we are running away from someone or have some other disturbing situation, are often nothing more than the brain healing the nervous system while we sleep. We go through all kinds of daily junk and misery and when we are relaxed during sleep, all that nervous "electronic" junk, gets cleared out of our system. When it does, it can manifest as various images of nervousness or fear. Or, if you believe the religious side of things, our souls come to the fore during dreams and do the healing. If you are in a bad dream and can become conscious in the dream itself, you can usually dispel the hostile experiences there by praying while in the dream itself, or imaging God next to you in the dream. Many bad dreams are also simply caused by bad digestion, especially eating too soon before sleep. At a minimum we should really go to sleep at least 2 hours after our last meal. And, preferably, four would be best.