When discussing sleep, there are always two sides of the coin: the body and the soul. For the body's perspective, the Talmud refers to sleep as 1/60th of death — and for good reason. Our eyes are closed. Conscious powers become weakened, and we lose control of many of our faculties. Yet, for the soul, it is a time of rejuvenation. It is united with its Source above and spiritually refreshed and recharged.
Our sages say that during each day of the seven weeks of the counting, the Jews in the desert, rose to a higher spiritual level. So you can imagine that by the time they reached the 49th day of counting and the 49th level of holiness, they were on a much higher level than they were the day they began the counting. On the night before they received the Torah, having reached a higher level of understanding and sensitivity — precisely now they went to sleep, and overslept?! It just doesn’t make sense.
The Chassidic masters explain that G‑d gave us a soul and he clothed the soul in a body. We are fully aware of the fact that our body is what we see and experience. When the soul leaves the body, the body remains a corpse, like a doll; there’s nothing there. The body is essentially subservient to the soul. Now, even though there’s a great purpose in living in this world in a body, for if there wasn’t, G‑d would not have created a world and would not have put us in the world, nevertheless, it is clear that the soul is in a sense confined within the body. There is a certain restraint that the soul must undergo because it is in a body. If the soul was not in a body it wouldn’t have to stop serving G‑d in order to eat and sleep and wash the dishes. There are certain needs that the body has that put a damper on what the soul would want to do twenty-four hours a day. So the body, in a sense, prevents the soul from expressing itself fully, and from serving G‑d constantly. A person gets tired. A soul doesn’t get tired. After a while you get bored. You lose your train of thought. You can’t concentrate any more. You need to sleep, you need to rest, you need to have your coffee. We’re just human beings. So the body slows the soul down.
However, when a person sleeps, a totally different thing happens. During the time of sleep, even though the person is obviously still alive, the heart still beats and the person still breathes, nevertheless, a segment of the soul leaves the body during the time of sleep.
During sleep there is a loss of consciousness. One does not fully hear, nor speak, nor see. There is an idea of death, a whisper of death — the Talmud calls sleep one sixtieth of death. Many people die in their sleep. Because during sleep everything slows down. The heart, the respiration, everything functions at a much slower pace than when the person is awake. During sleep the soul that was inside the body rises to its source above.
