If you wish to escape from Satan in religion, you must give heed to three things, without which you cannot be in safety from his cunning. In the first place I would have you take this general advice, which you should never forget, namely, that it is the ordinary practice of Satan to deceive those who are going on to perfection by an appearance of good: he does not tempt them by what seems to be evil. He knows that they will scarcely regard that which they know to be wrong. You must therefore continually distrust what seems to be good, and especially when obedience does not intervene. The remedy here is the direction of one whom you ought to consult. Let this then be the first precaution.
Never set about anything, however good or charitable it may seem, either to yourself or to any other, whether in the community or out of it, except under obedience, unless you are bound to do it by the rule of your order. If you do this you will acquire merit, and be in security. You will be safe against yourself and against evil; you will also avoid evils of which you are ignorant, and of which God will require an account one day. If you do not observe this in little things as well as in great, notwithstanding your apparent progress, Satan will most certainly deceive you little or much. Even if your whole error consist in your not being guided in everything by obedience, you are plainly wrong, because God wills obedience rather than sacrifice (1 Kings 15:22), and the actions of a religious are not his own, but those of obedience, and if he withdraws them from the control of obedience, he will have to give account of them as lost.
The second precaution is a very necessary one, because the devil interferes exceedingly in the matter to which it refers. The observance of it will bring great gain and profit, and the neglect great loss and ruin. Never look upon your superiors, be they who they may, otherwise than if you were looking upon God, because they stand in His place. Keep a careful watch upon yourself in this matter, and do not reflect upon the character, ways or conversations or habits of your superior. If you do, you will injure yourself, and you will change your obedience from divine into human, and you will be influenced by what you see in your superior, and not by the invisible God Whom you should obey in that person. Your obedience will be in vain, or the more barren the more you are troubled by the untowardness, or the more you are pleased by the favour, of your superior. I tell you that a great many religious in the way of perfection are ruined by not looking upon their superiors as they ought; their obedience is almost worthless in the eyes of God, because influenced by human considerations. Unless you force yourself therefore to be indifferent as to who your superior may be, so far as your private feelings go, you will never be spiritual, neither will you faithfully observe your vows.
The third precaution against Satan is this: strive with all your heart after humility in thought, word and deed, taking more pleasure in others than in yourself, giving way in every thing to others, and doing so as far as you can from a sincere heart. In this way you will overcome evil with good, drive the devil away, and have joy in your heart. Deal thus with those who are less agreeable to you; for be assured, if you do not, you will never have true charity nor make progress in it. Be always more ready to receive instruction from any one than to give it, even to the least of your fellow brethren and sisters.
If you wish to be delivered from the uneasiness and imperfections of which the habits and conversation of the religious may be the occasion, and profit by everything that may happen, you must keep in mind that you entered the community to be mortified and tried, and that all those in authority in it are there, as in truth they are, for that purpose. Some have to mortify you by words, others by deeds, and others by what they think of you; in all this you are to submit yourself, unresisting as a statue to the polisher, the painter and the gilder of it. If you do not, you will never be able to live as you ought with the religious in the monastery; you will not attain to holy peace, nor will you escape from much evil.
Never omit any practices, if they are such as befit you, because they are disagreeable; neither observe them because they are pleasant, unless they be as necessary as those which are not agreeable. Otherwise you will find it impossible to acquire firmness, and conquer your weakness.
In all your spiritual exercises never set your eyes upon the sweetness of them and cling to it, but rather on that in them which is unpleasant and troublesome, and accept it. If you do, you will never destroy self-love, nor acquire the love of God.