Saint Theophan tells us that it is through asceticism that we purify our heart. He outlines two ways for doing this. The first is with ascetic labors and the other is by turning our mind to God. It is in this second way where God helps us by burning away the impurities. This latter way is known as the Jesus Prayer.
Saint Gregory the Sinaite says, "we acquire God by either activity,labor, or the artful calling on the name of jesus."
The Jesus Prayer is thought by many to be shortest path. Saint Theophan says, "It illuminates, strengthens, enlivens, conquers all enemies visible and invisible, and leads us to God."
Learning the practice of the Jesus prayer is seen as an art.
Saint Theophan advises as follows:
Standing with awareness and attention in the heart, pronounce ceaslessly: "Lord Jesus Christ, Son of God, have mercy on me." without picturing any sort of image or face, but with faith that the Lord will see you nd attend to you.
In order to become strong in this, you should assign a time in the morning or revening––fifteen minutes, a half hour, or more––however much you can, just for saying this prayer. It should be after morning or evening prayers, standing or sitting. This will place the beginnings of a habitual practice.
Then during the day, force yourself minute -by-minute to say it, no matter what you are doing.
It will become more and more habitual, and then it will start working as if by itself during any work or occupation. The more routinely you take it up, the faster you will progress.
Your awareness should be kept unfailingly in the heart, and during the pracice your breath should lighten as a result of the tension with which you practice it. But the most important condition is faith that God is near and hears us. Say the prayer into God's ear.This practice is not as easily as it sounds at first You will run into difficulties. It will develop in you in stages. At first it will be an activity, then will become a mental prayer and finally a prayer that repeats itself unceasingly in your heart.
It is easy to become deceived in the practice of this prayer so it is best to have a guide. Remember it is not a device, or a technique like many eastern methods of meditation. It is first a prayer to God. Saint Theophan advised that deception can come mainly by placing your attention on the head rather than the heart.. Focus on you chest as you say it. He says, "Whoever has the attention centered in the heart is safe. Even safer is the one who fall down before God every hour in contrition, with the prayer that he be delivered from deception."
Much has been written on this prayer by our Church Fathers see the articles on this web page (www.OrthodoxPrayer.org/Jesus Prayer/). Read them. You will also see some books listed there.
Saint Theophan reminds us that "all the fruits of these labors come from the spirit of zeal and quest.... Always bear in mind that the spirit life must burn within, and we must in humility and pain of heart fall down before God our Savior."
Reference: Path to Salvation, pp 258-259
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