St. Hesychios the Priest ca. 8th-9th cent.?
Just as a man blind from birth does not see the sun’s light, so one who fails to pursue watchfulness does not see the radiance of divine grace. He cannot free himself from evil thoughts, words and actions, and because of these thoughts and actions he will not be able to freely pass the lords of hell when he dies. (Philokalia Vol. 1, pg. 163: On Watchfulness and Holiness 4)