Observe your thoughts, and beware of what you have in your heart and your spirit, knowing that the demons put ideas into you so as to corrupt your soul by making it think of that which is not right, in order to turn your spirit from the consideration of your sins and of God.
If a man purifies his heart and uproots from it all sin against the Lord; if he labors diligently to acquire Divine knowledge and succeeds in seeing with his mind that which is invisible to many, he must not through this exalt himself over others. Who among creatures is purer than an incorporeal being and who has more knowledge than an Angel? Yet, having exalted himself he was cast down from heaven like lightning. His pride was regarded by God as impurity.
St. Paul says: 'The person engaged in spiritual warfare exercises self control in all things' (I Cor. 9:25). Aware of all that is said in divine Scripture, let us lead our life with self-control, especially in regard to food.
Meekness and humility of heart are virtues without which it is impossible to inherit the Heavenly Kingdom, to be happy on earth, or to experience inner calm.
Fasting, while of value in itself, is not something to boast of in front of God, for it is simply a tool for training those who desire self-restraint. The ascetic should not feel proud because he fasts; no artist ever boasts that his accomplishment is simply due to his tools; but he waits for the work itself to give proof of his skill.
Among the virtues which must be instilled in a child's heart with special persistence, an important and fundamental place belongs to truthfulness, that is to say, a feeling of love for truth and an aversion towards falsehood. After obedience, this virtue should be given second place. If falsehood is the root of all sin, truth is the beginning and foundation for nearly all virtues, and for this reason parents must direct their attention primarily at nurturing truthfulness in children.
Whether you pray with brethren or alone, try to pray not simply as a routine, but with conscious awareness of your prayer. Conscious awareness of prayer is concentration accompanied by reverence, compunction and distress of soul as it confesses its sin with inward sorrow.
It is not always possible to fulfill the usual rules; one must take circumstances into account and try to fulfill what they make possible, as far as one can. The demons themselves are not unmindful of this law. So, being in constant enmity with us, they prevent us from doing what is possible and urge us to do what is impossible.
To those who are just beginning to long for holiness, the path of virtue seems very rough and forbidding. It appears like this, not because it really is difficult, but because our human nature from the womb is accustomed to the wide roads of sensual pleasure. But those who have traveled more than half its length find the path of virtue smooth and easy. For when a bad habit has been subjected to a good one through the energy of grace it is destroyed along with the remembrance of mindless pleasures; and thereafter the soul gladly journeys on all the ways of virtue. At the beginning of the struggle, therefore, the holy commandments of God must be fulfilled with a certain forcefulness of will (cf. Matt. 11:12); then the Lord, seeing our intention and labor, will grant us readiness of will and gladness in obeying His purpose. For 'it is the Lord who makes ready the will' (Prov. 8:35, LXX), so that we always do what is right joyfully. Then shall we truly feel that 'it is God who energizes in you both the willing and the doing of His purpose' (Phil. 2:13).
Smoke from wood kindling a fire troubles the eyes; but then the fire gives them light and gladdens them. Similarly, unceasing attentiveness is irksome; but when, invoked in prayer, Jesus draws near, He illumines the heart; for remembrance of Him confers on us spiritual enlightenment and the highest of all blessings.
Let us go forward with the heart completely attentive and the soul fully conscious. For if attentiveness and prayer are daily joined together, they become like Elias' fire-bearing chariot, raising us to heaven. What do I mean? A spiritual heaven, with sun, moon and stars, is formed in the blessed heart of one who has reach a state of watchfulness, or who strives to attain it.