Sleep is a particular state of nature, an image of death, inactivity of the senses. Sleep is one, but, like desire, its sources and occasions are many; that is to say, it comes from nature, from food, from demons, or perhaps, sometimes, from extreme and prolonged fasting, through which the flesh is weakened and at last longs for the consolation of sleep.
The demons, murderers as they are, push us into sin. Or if they fail to do this, they get us to pass judgment on those who are sinning, so that they may defile us with the stain which we ourselves are condemning in another.
You must set about rooting out the very desire to have things pleasant, to get on well, to be contented. You must learn to like sadness, poverty, pain, hardship. You must learn to follow privately the Lord's bidding: not to speak empty words, not to adorn yourself, always to obey authority, not to look at a woman with desire, not to be angry and much else. For all these biddings are given us not in order for us to act as if they did not exist, but for us to follow: otherwise the Lord of mercy would not have burdened us with them. If any man will come after me, let him deny himself, He said (Matthew 16:24), thereby leaving it to each person's own will ... and to each person's endeavor: let him deny himself.
When you close the doors to your dwelling and are alone you should know that there is present with you the angel whom God has appointed for each man...This angel, who is sleepless and cannot be deceived, is always present with you; he sees all things and is not hindered by darkness. You should know, too, that with him is God, who is in every place; for there is no place and nothing material in which God is not, since He is greater than all things and holds all men in His hand.
Do not hesitate to go late at night to those places where you usually feel afraid. But if you yield only a little to such weakness, then this childish and ridiculous infirmity will grow old with you. As you go on your way, arm yourself with prayer. When you reach the place, stretch out your hands. Flog your enemies with the name of Jesus, for there is no stronger weapon in heaven or earth. When you get rid of the disease of fear, praise Him who has delivered you. If you continue to be thankful, He will protect you for ever.
Those who live in obedience are strangers to love of money. For where even the body has been given up, what is left to be one's own? Only in one way can they be harmed, namely by being ready and quick to go from place to place. I have seen material possessions make monks patient to remain in one place. But I praise those who are pilgrims for the Lord.
Do not hesitate to go late at night to those places where you usually feel afraid. But if you yield only a little to such weakness, then this childish and ridiculous infirmity will grow old with you. As you go on your way, arm yourself with prayer. When you reach the place, stretch out your hands. Flog your enemies with the name of Jesus, for there is no stronger weapon in heaven or earth. When you get rid of the disease of fear, praise Him who has delivered you. If you continue to be thankful, He will protect you for ever.
As long as the flesh is in full health, let us observe abstinence at all times and in every place. When it has been tamed (which I do not suppose is possible this side of the grave), then let us hide our accomplishment.
One should not ponder divine matters on a full stomach, say the ascetics. For the well-fed, even the most superficial secrets of the Trinity lie hidden.
Just as over-drinking is a matter of habit, so too from habit comes over-sleeping. Therefore we must struggle with the question of sleep, especially in the early days of obedience, because a long-standing habit is difficult to cure.