Prayer offered up at night possesses a great power, more than the prayer of the day-time. Therefore all the righteous prayed during the night, while combatting the heaviness of the body and the sweetness of sleep and repelling corporeal nature.

And again, ‘At midnight I arose to give thanks unto Thee for the judgments of Thy righteousness.’ | And for every entreaty for which they urgently besought God, they armed themselves with the prayer of night vigil, and at once they received their request. | Homily 75, p. 523