As a general rule, decide whether a thing is permissible by the effect it produces within. Permit yourself what is constructive, but never what is destructive.
Empty your mind of these two things: the belief that you are deserving of great things, or the thought that any man is beneath you. If you do this anger will never be permitted to rise up within you.
One cannot approach the knowledge of the truth with a disturbed heart. Therefore we must try to avoid everything that disturbs our heart, that causes forgetfulness, excitement or passion, or that awakens unrest. We must free ourselves as much as possible from all fuss and flutter and ado over vain things. Yes, when we serve the Lord we shall not be troubled about many things, but always keep in mind that one thing is needful (Luke 10:41).
Grace is the food and clothing of the saints. It wakens grief in a man's heart, making him dissatisfied and moving him to seek the reason of this dissatisfaction. Grace gives sorrow and grace comforts; showing us the poverty of all things, it engenders in us a repentant sorrow for having fallen short of the love of God... One who is possessed by such sorrow will always grieve, for he thinks of God's offended love and not of the fear of hell. It is a grief of love.
Disciplined piety feeds the soul on holy thoughts. What can be more blessed than to imitate on earth the chorus of the angels; to begin the opening day with prayer, honouring the Creator with hymns and songs; and when the sun is up to turn to work, always accompanied by prayer, and to season one's labours with singing? Cheerfulness and freedom from sorrow are the gifts which the soul received from the singing of hymns.
The day will come when you are toiling at self-observation and self-constraint, and the adversary will come up and mumble in your ear, 'This will all happen eventually. You’ve been working hard, now take it easy a little bit!' This is such a tempting suggestion that it does not immediately occur to you that you should counter it, or that it is so bad that however little you give in to it, it will cause such inner disturbance. Indulging yourself is just like a tiny hole in a dam. Once a hole has formed, the dam cannot hold; the water will inevitably destroy it. Indulgence does the same thing inside of us; everything will be dispersed, so it will be necessary to start all over again to restore ourselves. Fear this as your most evil enemy, although he speaks with the sweetest words.
The love of God is not something we learn from another. Neither did we learn from another how to love the sunshine or how to defend our life. Nor has anyone taught us how to love our parents, or those who have reared us. And so, indeed much more, learning how to love God does not come to us from outside. But in the very commencement of the life of man, there is placed within us a certain seminal conception, having, from itself, the beginnings of a natural propensity towards this love.
At this point the zealous man looks inward, and what do you think he finds there? Ceaseless wandering of thoughts, constant onslaughts from the passions, hardness and coldness of heart, obstinacy and disobedience, desire to do everything according to his own will. In a word, he finds everything within himself in a very bad state. And seeing this, his zeal is inflamed, and he now directs strenuous efforts to the development of his inner life, to controlling his thoughts and the dispositions of his heart. From directions on inner spiritual life he discovers the necessity of paying attention to oneself, of watching over the movements of the heart. In order not to admit to anything bad, it is necessary to preserve the remembrance of God. And so he sets to work to achieve this remembrance. But his thoughts can no more be arrested than the wind; his bad feelings and worthless impulses can no more be evaded than the stench of a corpse; his mind, like a wet and frozen bird, cannot rise to the remembrance of God. What is to be done? Be patient, they say, and go on working. Patience and labor are exercised, but all within remains the same. At last someone of experience is found who explains that all is inwardly in disorder because the forces within are divided: mind and heart each go their own way. Mind and heart must be united; then wandering of thoughts will cease, and you will gain a rudder to steer the ship of your soul, a lever by which to set in movement all your inner world. But how can one unite mind and heart? Acquire the habit of praying these words with the mind in the heart, 'Lord Jesus Christ, Son of God, have mercy upon me'. And this prayer, when you learn to perform it properly, or rather when it becomes grafted to the heart, will lead you to the end which you desire. It will unite your mind with your heart, it will cut off your wandering thoughts, and give you the power to govern the movements of your soul.
Many abstain from meat, milk and other food which God has not forbidden and which was even given as a blessing of people who have learned the truth and know how to partake of these things with thanksgiving (I Tim. 4:34). But the same abstemious, devout-living people, give scandal by their action, and spread scandal with their tongue like an incendiary fire.
The simplest means for confining the will within its proper bounds lies in disposing children to do nothing without permission. Let them be eager to run to their parents and ask: May I do this or that? They should be persuaded by their own experience and that of others that to fulfill their own desires without asking is dangerous; they should be put in such a frame of mind that they even fear their own will.
Knowing the exact nature of everything, God permits each person to be tested according to his strength. As St. Paul puts it: 'God is to be trusted not to let you be tried beyond your strength, but with the trial He will provide a way out, so that you are able to bear it' (1 Cor. 10:13).
Solitude offers us an excellent opportunity for calming our passions and giving our reason time to remove them thoroughly from our soul. For just as wild animals can be soothed by being stroked, so all our anger, fear and stress, which poison and disrupt our soul, can be soothed by an atmosphere of peace where the freedom from constant disturbance ensures that our soul can be brought more easily under the power of reason.