Ramana Maharshi
Ramana Maharshi Quotes about Sleep
Every living being longs always to be happy, untainted by sorrow; and everyone has the greatest love for himself, which is solely due to the fact that happiness is his real nature. Hence, in order to realize that inherent and untainted happiness, which indeed he daily experiences when the mind is subdued in deep sleep, it is essential that he should know himself. For obtaining such knowledge the inquiry 'Who am I?' in quest of the Self is the best means.
If the mind falls asleep, awaken it. Then if it starts wandering, make it quiet. If you reach the state where there is neither sleep nor movement of mind, stay still in that, the natural (real) state.
Bliss is not something to be got. On the other hand you are always Bliss. This desire [for Bliss] is born of the sense of incompleteness. To whom is this sense of incompleteness? Enquire. In deep sleep you were blissful. Now you are not so. What has interposed between that Bliss and this non-bliss? It is the ego. Seek its source and find you are Bliss.
That which is not present in deep dreamless sleep is not real.
Apart from thoughts, there is no independent entity called the world. In deep sleep there are no thoughts, and there is no world. In the states of waking and dream, there are thoughts, and there is a world also. Just as the spider emits the thread (of the web) out of itself and again withdraws it into itself, likewise the mind projects the world out of itself and again resolves it into itself.
The activity affected by causes like fainting, sleep, excessive joy, grief, possession by spirits, fear etc goes to the heart, its own place.