The healing of the demoniac boy happened after the Transfiguration of Jesus. This is where Jesus went up on a mountain and appeared with Moses and Elijah. The disciples, Peter, James and John had witnessed the Transfiguration of Jesus. The disciples who stayed at the base of the mountain had encountered a problem casting out a demon. Jesus rebuked the demon and it came out of him, and the boy was cured instantly. When His disciples asked Him why they could not cast out the demon, He said to them “This kind can come out only through prayer.”