A man who falls into sin is different from the way he was created. He is different, because he changes by his own actions the way he was meant to be. Man renounces himself when he becomes a different person through repentance. He leaves a corrupted man, which he had become through sin, and becomes such as he once was created, through mercy.
To pray with self-constraint is in our power, whereas to pray with compunction depends upon God. We must pray with what prayer we can, and for our self-constraint God will give us compunction also in due time, when this is pleasing to Him.
Because the nous can get tired by the reciting of all the words of the Jesus Prayer, it is necessary to make it shorter: 'Lord Jesus Christ, have mercy on me.' Or, 'Lord have mercy on me.' Or, 'Lord Jesus.' As the Christian progresses in the work of the Jesus Prayer, he can decrease the words. He can even sometimes insist on the word 'Jesus,' which he says repeatedly (Jesus, Jesus, Jesus, my Jesus)--a wave of calmness and joy rises in him. He should remain in this sweetness which appears and not stop the prayer, even if his usual rule of prayer is finished. He should seize and keep this warmth of his heart and take advantage of this gift of God! For it is a great gift which God sends from on high. The warmth of the heart helps the nous effectively to be fixed on the words of the Jesus Prayer ... If one wants to spend all day in prayer, he should follow the recommendation of the Holy Fathers. He should pray for an hour, read for an hour and then again spend an hour in prayer. When he is engaged in manual work too, he should try to say the Jesus Prayer.
You must flee from sensual things. Verily, every time a man comes close to a struggle with sensuality, he is like a man standing at the edge of a deep lake, and the enemy throws him in whenever he likes. But if the man lives far from sensual things, he is like one who stands at a distance from the lake, so that even if the enemy entices him in order to throw him to the bottom, God sends him help at the very moment that the enemy is drawing him away and doing him violence.
In words of boastfulness and self-justification there always lie concealed contrariness and pride, from which God turns away. After sinning one ought immediately to 'flee.' But you say, where? To the calm haven of heartfelt repentance.
He who wishes to purify his faults purifies them with tears, and he who wishes to acquire virtues, acquires them with tears; for weeping is the way the Scriptures and our Fathers give us, when they say 'Weep!' Truly, there is no other way than this.