Sleep and dreaming tend to be looked at apart from one another , if only because REM sleep is so different from other sleep. We do not conceive that they could serve the same purpose. And yet, they co-exist , and set each other up in the sleep cycle. We seem intuitively to believe that non-REM sleep serves a purpose of rest , while REM sleep, or dreaming, serves another purpose, more psychological in nature. Here we have seen that energy stores, temperature regulation, and circadian rhythms all may have something to do with sleep.
Sleep is a highly regulated , necessary body process.
The body needs a certain amount of sleep each day. It is plausible that, as different responses of the body are affected differently by sleep deprivation that sleep serves different purposes for those parts. Sleep could be a cover for a number of body processes that work better when the body is at rest , including dreaming. As for the divine revelation of dreams, that can either be taken a face-value or studied by anthropologists to learn more about how religions come into being.