The nerves and the glands, the intestines and the muscles all continue their work. The sleeper looks like a lifeless and prostrate figure, but suddenly he awakens and comes back to life. Sleep and awakening are in fact comparable to death and resurrection. Then He keeps the soul that is destined to die at that time, and returns the others to life for a set period. In the view of the Qur'an, sleep is outwardly the suspension of the natural forces in man, but it is at the same time a return of man's spirit to his inner being.
Sleep is the lesser death, and death is the greater sleep.
In both cases the spirit is transferred to a different world. The difference is that on waking up a person is unaware that he has returned from a journey, whereas for the one who dies all things become clear. Dreams have been divided into several categories. A large proportion of dreams derive from the hopes and desires of the dreamer, or reflect occurrences he has experienced. Another major category consists of confused dreams that simply reflect man's imaginings and illusions.