Segmented sleep

The present study is less a suggestion of any fresh finding in biblical matters than a plea that the awareness of a detail of premodern life be brought to bear on various biblical passages, namely, the pattern of segmented sleep. It is a matter that has been forgotten by those who benefit from artificial illumination, which is to say almost everyone in the modern world. 

Current research by physiologists, anthropologists, and historians has made it clear that the pattern of human sleep in preindustrial society has been strikingly different from the one now taken for normal…[Ekirch] There is every reason to believe that segmented sleep, such as many wild animals exhibit, had long been the natural pattern of our slumber before the modern age, with a province as old as mankind. Most notable is the fact that first sleep often ends with vivid dreams…distinguished by their narrative quality.

There are two similar parables about activity at midnight, of the wise and foolish bridesmaids (Mt 25:1-3) and the master home from the wedding feast (Lk 12:36-38). Both parables describe wakefulness and the preparation of a meal in the middle of the night.

Even the monastic practice of vigils (matins, prayer at midnight), which to us might be looked upon as an extreme asceticism, is better viewed as the community use of a normal sleep pattern…Praying in the middle of the night is a convention of the Psalms (Pss 63:7; 77:7; 119:55,62,148). W. L. Holladay, "Indications of Segmented Sleep in the Bible," CBQ 69 (2007). 

That's just a sample. The entire article is informative. And it sheds further light (pardon the pun) in a particular interest of mine: the biblical symbolism of light and dark. When, for example, modern readers study the references light and darkness, day and night, dawn and dusk, sun, moon, and stars in Gen 1, there's a myopic focus on units of light as units of time. Yet this motif had a much richer range of connotations for ancient Jews. And in this particular instance, the experience of sleeping and dreaming, which–not coincidentally–is a prominent theme in Genesis.