Suppose, however, that getting up from sleep awakens you not only in the night, but to the night. Once, in monasteries and nunneries, night watch was called vigil, and sleep was shortened on purpose so that when the Lord of Temptations came calling and his minions tried to enter your thoughts at night you could ward them off. The early Christian monks who lived in desert caves tried to banish sleep altogether, since pagan powers were thought to approach pious souls through dreams. . . So the devout person intent upon building a strong character was less eager to sleep than to keep watch at night. Character depended on fending off the fantasies and voices that threatened to lead one away from the Christian path. To fend them off, the devout had to open their eyes to the night so as to discriminate among the spirits.
— James Hillman, The Force of Character