Saint Isaac the Syrian (7th century), monk at Nineveh, near Mosul in present day Iraq
"Light your lamps"
Prayer offered during the hours of night possesses great power, even more than that offered during the day. That is why all the saints were in the habit of praying at night, combating the body's drowsiness and the sweetness of sleep and overcoming their bodily nature. The prophet also said: «I am wearied with sighing; every night I flood my bed with weeping» (Ps 6,7) as he uttered heartfelt sighs in impassioned prayer. And elsewhere: «At midnight I rise to give you thanks because of your just ordinances, O just God» (Ps 119,62). For every request for which the saints desired to importune God they armed themselves with nocturnal prayer and at once received what they were asking for. Satan himself fears nothing as much as prayer offered during the night watches. Even if they are accompanied by distractions it does not return fruitless so long as something inappropriate is not being asked for. That is why Satan engages in severe combat against those who keep watch at night so as to deter them from this practice if he can, especially if they show themselves to be persevering. But those who are in any way defended against his pernicious wiles and have tasted the gifts God grants at these times of vigil and have had personal experience of the greatness of the help God gives them, wholly despise him, he and all his craftiness.