People in India have always been saying that sleep is a short duration of death, and death is a long sleep — qualitatively they are the same. Sleep is a day-to-day death. Death is a life-to-life phenomenon, a life-to-life sleep. Every day you are tired. You fall into sleep and you regain your vitality, your aliveness in the morning; you are reborn. After a life of seventy or eighty years you are tired completely. Now such short durations of death won't do; you need a great death. After that great death or great sleep, you are reborn with a totally new body.
Once you can know dreamless sleep and can be aware in it, then there will be no fear of death. No one has ever died, no one can die — that is the only impossibility.
Just a day before I was telling you that death is the only certainty, and now I say to you that death is impossible. No one has ever died and no one can die — that is the only impossibility — because the universe is life. You are again and again reborn, but the sleep is so deep that you forget your old identity. Your mind is washed clean of the memories.
Think of it in this way. Today you are going to sleep: it is just as if there were some mechanism — and soon we will have this — like that which can erase on a tape recorder, which can wipe a tape clean so that whatsoever was recorded is no more there. The same is possible with memory, because memory is really just a deep recording.
Sooner or later we will have a mechanism which can be put on the head and it will clean your mind completely. In the morning you will no longer be the same person because you won't be able to remember who it was who went to sleep. Then your sleep will look like death. There will be a discontinuity; you won't be able to remember who went to sleep. This is happening naturally. When you die and you are reborn, you cannot remember who died. You start again.
With this technique, first you will become the master of your dreams — that is, dreaming will cease. Or if you want to dream you will be able to dream, but dreaming will become voluntary. It will not be non-voluntary, it will not be forced upon you; you will not be a victim. Then the quality of your sleep will become just like that of death. Then you will know that death is sleep.
OSHO