7 But if for your part you desire to be a monk and not merely to seem one, be more careful of your soul than of your property; for in adopting a religious profession you have renounced this once for all. Let your garments be squalid to show that your mind is white; and your tunic coarse to prove that you despise the world. But give not way to pride lest your dress and language be found at variance. Baths stimulate the senses and must, therefore, be avoided; for to quench natural heat is the aim of chilling fasts. Yet even these must be moderate, for, if they are carried to excess, they weaken the stomach and by making more food necessary to it promote indigestion, that fruitful parent of unclean desires. A frugal and temperate diet is good for both body and soul.
See your mother as often as you please but not with other women, for their faces may dwell in your thoughts and so
A secret wound may fester in your breast.
The maidservants who attend upon her you must regard as so many snares laid to entrap you; for the lower their condition is the more easy is it for you to effect their ruin. John the Baptist had a religious mother and his father was a priest. Yet neither his mother's affection nor his father's wealth could induce him to live in his parents' house at the risk of his chastity. He lived in the desert, and seeking Christ with his eyes refused to look at anything else. His rough garb, his girdle made of skins, his diet of locusts and wild honey were all alike designed to encourage virtue and continence. The sons of the prophets, who were the monks of the Old Testament, built for themselves huts by the waters of Jordan and forsaking the crowded cities lived in these on pottage and wild herbs. As long as you are at home make your cell your paradise, gather there the varied fruits of scripture, let this be your favourite companion, and take its precepts to your heart. If your eye offend you or your foot or your hand, cast them from you. To spare your soul spare nothing else. The Lord says: “whosoever looks on a woman to lust after her has committed adultery with her already in his heart.” “Who can say,” writes the wise man, “I have made my heart clean?” The stars are not pure in the Lord's sight; how much less men whose whole life is one long temptation. Woe be to us who commit fornication every time that we cherish lust. “My sword,” God says, “has drunk its fill in heaven;” much more then upon the earth with its crop of thorns and thistles. The chosen vessel who had Christ's name ever on his lips kept under his body and brought it into subjection. Yet even he was hindered by carnal desire and had to do what he would not. As one suffering violence he cries: “O wretched man that I am! Who shall deliver me from the body of this death?” Is it likely then that you can pass without fall or wound, unless you keep your heart with all diligence, and say with the Saviour: “my mother and my brethren are these which hear the word of God and do it.” This may seem cruelty, but it is really affection. What greater proof, indeed, can there be of affection than to guard for a holy mother a holy son? She too desired your eternal welfare and is content to forego seeing you for a time that she may see you for ever with Christ. She is like Hannah who brought forth Samuel not for her own solace but for the service of the tabernacle.
The sons of Jonadab, we are told, drank neither wine nor strong drink and dwelt in tents pitched wherever night overtook them. According to the psalter they were the first to undergo captivity; for, when the Chaldæans began to ravage Judah they were compelled to take refuge in cities.
Source: Letters (New Advent)