By what is sobriety of mind preserved? From whence does sleepiness and the coldness of our thought come which extinguish the holy warmth in the soul and fervor towards God?
This holy warmth is preserved by sober thought, warm zeal, so as manfully and patiently at every hour, with all one's power, to guard one soul from weakness. This zeal removes every opposition, drowsiness. laziness, weight, weakness, and despondency. This zeal is strengthened, is aroused, is enkindled, and is the defender of the house of virtues. At the same time, one must fulfill the usual bows or prostrations, handiwork, and be refreshed in the air, for from this there is great help and power against sleep, laziness, weight, and weakness. And in prayer one must stand in a fresh place that in cool, because then the blood does not circulate through the legs. This is not only for the infirm and those sickly of body, but for those who are healthy. In a warm room, on the other hand, one is attacked by drowsiness, sleep, weight, heaviness, weakness, and this hinders and overcomes the ascetic. Nothing so weighs upon solitary desert dwellers than these infirmities. Besides, be heedful to yourself. From tumult is born much speaking, idle talking. From idle talking, idleness. From idleness, laziness. From laziness, despondency. From despondency, sleep. And from sleep, the deprivation of good deeds. And then a man falls into every evil.