For the sake then of keeping watch, our Lord advised above that our loins should be girded, and our lamps burning, for light when placed before the eyes drives away sleep. The loins also when tied with a girdle, make the body incapable of sleep. For he who is girt about with chastity, and illuminated by a pure conscience, continues wakeful.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: ubi sup.