My cat sleeps a lot (no, this is not my cat - but it's cute, don't you think?)
A few nights ago I lay down to go to sleep for the night - and had suddenly the thought that this was a very strange thing to do. I lay down and was, indeed, ready for bed - but my thoughts went to the work I had been doing, and to the work I would do the next day. And I lay - for a little while! :-) - pondering this: why do we sleep?
To retort that it's a 'biological need' only pushes the matter farther back. Why is it a biological need? Do all creatures sleep? This article appears to indicate that most animals sleep. It says "Rats kept from sleeping die within a couple of weeks, but the exact function of sleep is still unknown."
There is an ambiguity about sleep. The Scriptures never mention sleep as something that will happen in Heaven - but it is often likened to death. Death is called 'sleep' more than once. And a cemetery is just a dormitory - a κοιμητήριον - the Greek means a sleeping place.
Yet we are to 'watch' - the Greek is αγρυπνειτε - stay awake! It is the Day of the Lord - never the night. We are to work whilst it is day - the night cometh when no man can work.
The night prayer of the Church - Compline - ends with the recital of the Nunc Dimittis, the Song of Simeon, which begins with "Now lettest Thou Thy servant depart in peace ..." - and the antiphon for the prayer is "Keep us safe, Lord, while we are awake, and guard us as we sleep, so that we can keep watch with Christ and rest in peace."
I said I was muddled. I do think that sleep is a little death. It is - and we need not fear it. It is that which 'knits up the ravel'd sleave of care.' It is the rest that God gives us to be strong for our duties. When we die, we will be watched over by Him, if we die in friendship with Him. But it is a reminder - a reminder that we are not sufficient in ourselves. If we could do without sleep - be always on the go, always doing - we would, perhaps, be tempted to forget that we begin our being out of nothing, by His call; we live the first nine months of our lives in passive reception of the means of our lives; we must cease our activity 8 hours or so in 24; and at the end we will - God grant it! - rest in the Lord, knowing that it is by Him that we will be raised to the wakening that is followed by no dying, no sleeping - and not by ourselves.