From the moment we fall asleep our soul moves away from our physical body & goes to join the universal Soul

Sleep - why it is necessary for our survival

"From the moment we fall asleep our soul moves away from our physical body and goes to join the universal Soul. During the body's rest, an entire process of cleansing and purification takes place. Subtle ties known as the 'silver cord' keep the soul connected to the physical body when it leaves it. On its return, the soul finds the house swept, cleaned and washed, and it can take up its work again.
If the soul did not leave the body in this way, we would die from poisoning and asphyxiation, because the work of cleansing could not be done. You may wonder where these toxins and poisons come from. They are produced quite simply because life is a combustion. All the physical, emotional and mental activities we know as 'life' give off forces, but they also leave behind impurities which take a while to be eliminated. So it is necessary for the soul to withdraw from the body so the cleansing can take place. Sleep is the solution that cosmic Intelligence has found so that we can continue to live."