John Chrysostom — as excerpted in the Catena Aurea on Luke 6:12-16

“(Hom. ad Pop. Ant. 42. et in Act. c. 16. Ed. Lat.) Rise then thou also at night time. The soul is then purer, the very darkness and great silence are in themselves enough to lead us to sorrow for our sins. But if thou lookest upon the heaven itself studded with stars as with unnumbered eyes, if thou thinkest that they who wanton and do unjustly in day time are then nothing different from the dead, thou wilt loathe all human undertakings. All these things serve to raise the mind. Vain-glory then disquiets not, no tumult of passion has the mastery; fire does not so destroy the rust of iron as nightly prayer the blight of sin. He whom the heat of the sun has fevered by day is refreshed by the dew; nightly tears are better than any dew, and are proof against desire and fear. But if a man is not cherished by the dew we speak of, he withers in the day. Wherefore although thou prayest not much at night, pray once with watching, and it is enough; shew that the night belongs not only to the body, but to the soul.”