If someone should ask: how am I to pray?, the answer is very simple: fear God. Experience of the fear of God arouses attention and consciousness in the heart and forces it to stand with devotion before God.
He who stands by a fire is warmed by it, and he who turns to the Lord with his mind and heart is warmed by the fervor of His love, and himself begins to return a warm disposition towards Him...The love of God is shed abroad in our hearts... (Rom. 5:5).
When the blessed Eulogius saw an angel distributing gifts to the monks who toiled at all-night vigils, to one he gave a gold piece with the image of Our Lord Jesus Christ, to another a silver piece with a cross, to another a copper piece, to another a bronze piece, and to another nothing. The others who had remained in the church, left the church empty-handed. It was revealed to him that the ones who had obtained the gifts are those who toil at vigils and are diligent in prayers, supplications, psalms, chants, and readings. Those who received nothing or who left the church empty-handed are those who are heedless of their salvation, are enslaved to vainglory and the clamors of life, and stand feebly and lazily at vigils and whisper and jest.
Since the enemy watches you constantly, waiting for an opportunity to sow evil in you, be doubly watchful over yourself, lest you fall in the nets spread for you. As soon as he shows you some fault in your neighbor, hasten to repel this thought, lest it take root in you and grow. Cast it out, so that no trace is left in you, and replace it by the thought of the good qualities you know your neighbor to possess, or of those people generally should have. If you still feel the impulse to pass judgment, add to this the truth that you are given no authority for this and that the moment you assume this authority you thereby make yourself worthy of judgment and condemnation, not before powerless men, but before God, the all-powerful Judge of all.
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.
To more conveniently become accustomed to remembering God, the fervent Christian has a special means, namely, to repeat ceaselessly a brief prayer of two or three words. Mostly this is 'Lord, have mercy.' or 'Lord Jesus Christ, Son of God, have mercy on me, a sinner.' If you have not yet heard of this, then hear it now, and if you have not done it, then begin from this hour to do it.
Then we say: 'Forgive us our trespasses as we forgive those who trespass against us.' Brothers, praying thus, we should very much fear lest the Lord reply to these words of our prayer: 'The judgments you give are the judgments you will get, and the amount you measure out is the amount you will be given.' And you who ask this, see whether you did to no one what you did not want done to you. Therefore before we hear these words of the Lord, brethren, let us first examine our hearts as to whether we are with justice asking of the Lord what we have not denied to those asking us. We ask that our trespasses be forgiven us. God hears and He wants to forgive us, but only if we first pardon those who ask us to do likewise.
Keep both eyes open. This is the measure of humility: if a man is humble he never thinks that he has been treated worse than he deserves. He stands so low in his own estimation that no one, however hard they try, can think more poorly of him than he thinks of himself.
Fasting appears gloomy until one steps into its arena. But begin and you will see what light it brings after darkness, what freedom from bonds, what release after a burdensome life…
Our prayer reflects our attitude towards God. He who is careless of salvation has a different attitude toward God from him who has abandoned sin and is zealous for virtue but has not yet entered within himself and works for the Lord only outwardly. Finally, he who has entered within and carries the Lord within himself, standing before Him, has yet another attitude. The first man is negligent in prayer, just as he is negligent in life, and he prays in church and at home merely according to the established custom, without attention or feeling. The second man reads many prayers and goes often to church, trying at the same time to keep his attention from wandering and to experience feelings in accordance with the prayers which are read, although he is seldom successful. The third man, wholly concentrated within, stands with his mind before God, and prays to Him in his heart without distraction, without long verbal prayers, even when standing for a long time at prayer in his home or in church.... Every prayer must come from the heart and any other prayer is no prayer at all. Prayer-book prayers, your own prayers and very short prayers, all must issue forth from the heart to God, seen before you.
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.
He who is afraid of God's punishment has a slave-like fear of God, and it is this that makes him refrain from evil: 'Out of fear of the Lord men shun evil' (Prov. 16:6. LXX)... through fear of what threatens us we sinners may be led to repent and may seek deliverance from our sins...The more a man struggles to do good, the more fear grows in him, until it shows him his slightest faults, those which he thought of as nothing while he was still in the darkness of ignorance. When fear in this way has become perfect, he himself becomes perfect through inward grief: he no longer desires to sin but, fearing the return of the passions, he remains in this pure fear invulnerable. As the psalm puts it, 'The fear of the Lord is pure, and endures for ever' (Ps. 19:9. LXX). The first kind of fear is not pure, for it arises in us because of our sins. But, independent of sin, the person who has been purified continues to feel fear, not because he sins, but because, being human, he is changeable and prone to evil. In his humility, the further he advances through the acquisition of the virtues, the more he fears. This is natural; for everyone who possesses wealth greatly fears loss, punishment, dishonor, and the consequent fall from his high estate...The sign of the first kind of fear is hatred of sin and anger towards it, like someone wounded by a wild beast. The sign of perfect fear is the love of virtue and the fear of relapsing, since no one is unalterable.
In preparing for battle, however, do not think that you will always be victorious. Often there will be only hardship that will bring nothing but affliction... Provide yourself with only one thing, strong courage: no matter what happens, stay with what you have begun... No matter how life goes, whatever successes and failures there are, you should give all of this over to God's will.
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.