The most nor­mal form of un­ceas­ing prayer in the Or­tho­dox tra­di­tion is the Jesus Prayer. The Jesus Prayer is the form of in­vo­ca­tion used by those prac­tic­ing men­tal prayer, also called the "prayer of the heart". The words of the prayer most usu­ally said are "Lord Jesus Christ, Son of God, have mercy on me a sin­ner". The choice of this par­tic­u­lar verse has a the­o­log­i­cal and spir­i­tual mean­ing.

First of all, it is cen­tered on the name of Jesus be­cause this is the name of Him whom "God has highly ex­alted", the name given to the Lord by God Him­self (Лк. 1:31), the "name which is above every name" (Флп. 2:9-10, Еф. 1:21).

...for there is no other name given among men by which we must be saved (Деян. 4:12).

All prayer for Chris­tians must be per­formed in the name of Jesus: "if you ask any­thing in my name, I will do it" (Ин. 14:13-14).

The fact that the prayer is ad­dressed to Jesus as Lord and Christ and Son of God is be­cause this is the cen­ter of the en­tire faith re­vealed by God in the Spirit.

He said to them, "But who do you say that I am?"

Simon Peter replied, "You are the Christ, the Son of the Liv­ing God."

And Jesus an­swered, "Blessed are you… for flesh and blood has not re­vealed this to you, but my Fa­ther who is in heave… and on this rock I will build my Church…" (Мф. 16:16-18).

That Jesus is the Christ, and that the Christ is Lord is the essence of the Chris­t­ian faith and the foun­da­tion of the Chris­t­ian church. To be­lieve and pro­claim this is granted by the Holy Spirit.

...no one can say "Jesus is Lord" ex­cept by the Holy Spirit (1Кор. 12:3).

...every tongue should con­fess that Jesus Christ is Lord to the glory of God the Fa­ther (Флп. 2:11).

In call­ing Jesus the Son of God is to ac­knowl­edge God as His Fa­ther. To do this is, at the same time, to have God as one’s own Fa­ther, and this too is granted by the in­dwelling Spirit.

And when the time had fully come, God sent forth His Son, born of a woman, born under the law, to re­deem those who were under the law, so that we might re­ceive adop­tion as sons. And be­cause you are sons, God has sent the Spirit of His Son into our hearts, cry­ing "Abba! Fa­ther!" (Гал. 4:4-6).

When we cry "Abba! Fa­ther!" it is the Spirit Him­self bear­ing wit­ness with our spirit that we are chil­dren of God… (Рим. 8:15-16).

Thus, to pray "Lord Jesus Christ, Son of God" is al­ready to be a child of God, and al­ready to be cer­tain that the Holy Spirit is in you. In this way, the Jesus Prayer brings the Spirit of God into the heart of man.

"Have mercy on me a sin­ner" is the pub­li­can’s prayer. When ut­tered with hum­ble con­vic­tion it brings di­vine jus­ti­fi­ca­tion (Лк. 18:9-14). Gen­er­ally speak­ing, di­vine mercy is what man needs most of all. It is for this rea­son that the num­ber­less rep­e­ti­tion of the re­quest for the Lord’s mercy is found every­where in the prayers of, the Church.

And fi­nally, all men are sin­ners. To know this is a fact, and to con­fess it with faith is to be jus­ti­fied and for­given by God (Рим. 3:10-12, Пс. 14:1-3).

The Jesus Prayer ba­si­cally is used in three dif­fer­ent ways. First as the verse used for the "prayer of the heart" in si­lence in the hesy­chast method of prayer. Sec­ond as the con­tin­ual men­tal and un­ceas­ing prayer of the faith­ful out­side the hesy­chast tra­di­tion. And third as the brief ejac­u­la­tory prayer used to ward off temp­ta­tions. Of course, in the ac­tual life of a per­son these three uses of the prayer are often in­ter­re­lated and com­bined.

In the hesy­chast method of prayer the per­son sits alone in a bod­ily po­si­tion with his head bowed and his eyes di­rected to­ward his chest or his stom­ach. He con­tin­u­ally re­peats the prayer with each as­pi­ra­tion and breath, plac­ing his "mind in his heart" by con­cen­trated at­ten­tion. He emp­ties his mind of all ra­tio­nal thoughts and dis­cur­sive rea­son­ing, and also voids his mind of every pic­ture and image. Then, with­out thought or imag­i­na­tion, but with all proper at­ten­tion and con­cen­tra­tion he rhyth­mi­cally re­peats the Jesus Prayer in si­lence - hesy­chia means si­lence - and through this method of con­tem­pla­tive prayer is united to God by the in­dwelling of Christ in the Spirit. Ac­cord­ing to the fa­thers, such a prayer, when faith­fully prac­ticed within the total life of the Church, brings the ex­pe­ri­ence of the un­cre­ated di­vine light of God and un­speak­able joy to the soul. Its pur­pose is to make man a ser­vant of God.

...the mind when it unites with the heart is filled with un­speak­able joy and de­light. Then a man sees that the King­dom of heaven is truly within us.

When you enter the place of the heart… give thanks to God, and prais­ing His mercy, keep al­ways to this ac­tiv­ity, and it will teach you things which you will learn in no other way.

...when your mind be­comes es­tab­lished in the heart, it must not re­main idle, but it should con­stantly re­peat the prayer: "Lord Jesus Christ, Son of God, have mercy on me!" and never cease.

For this prac­tice, keep­ing the mind from dream­ing, ren­ders it in­vin­ci­ble against all sug­ges­tions of the devil and every day leads it more and more to love and long­ing for God (St. Nicepho­rus, Dis­course on So­bri­ety).

To prac­tice the hesy­chast method of prayer re­quires al­ways and with­out ex­cep­tion the guid­ance of a spir­i­tual guide, one must not use this method un­less one is a per­son of gen­uine hu­mil­ity and san­ity, filled with all wis­dom and peace. To use this method with­out guid­ance or hum­ble wis­dom, is to court spir­i­tual dis­as­ter, for the temp­ta­tions that come with it are many. In­deed, the abuses of the method be­came so great in re­cent cen­turies that its use was greatly cur­tailed. Bishop Theo­phan tells that the bod­ily pos­tures and breath­ing tech­niques were vir­tu­ally for­bid­den in his time since, in­stead of gain­ing the Spirit of God, peo­ple suc­ceeded only "in ru­in­ing their lungs" (The Art of Prayer, lgu­men Chari­ton).

Such abu­sive and abortive used of the method - it­self some­thing gen­uine and richly re­ward­ing were al­ready known in four­teenth cen­tury Byzan­tium when St. Gre­gory Pala­mas de­fended the tra­di­tion. And ev­i­dence ex­ists from as early as the fourth cen­tury to show that even then peo­ple were using the prayer fool­ishly and to no avail by re­duc­ing it to a "thing in it­self" and being cap­ti­vated by its form with­out in­ter­est in its pur­pose. In­deed, the idol­a­trous in­ter­est in spir­i­tual tech­nique and in the plea­sur­able ben­e­fits of "spir­i­tu­al­ity" and "mys­ti­cism" are the con­stant temp­ta­tions of the spir­i­tual life - and the devil’s most po­tent weapon. Bishop Theo­phan called such in­ter­est "spir­i­tual he­do­nism"; John of the Cross called it "spir­i­tual glut­tony" and "spir­i­tual lux­ury". Thus, by way of ex­am­ple from var­i­ous times and places, come the fol­low­ing ad­mo­ni­tions.

Those who refuse to work with their hands under the pre­text that one should pray with­out ceas­ing, in re­al­ity do not pray ei­ther. Through idle­ness… they en­tan­gle the soul in a labyrinth of thoughts… and make it in­ca­pable of prayer (St. Nilus of Sinai, Texts on Prayer).

As long as you pay at­ten­tion only to bod­ily pos­ture for prayer and your mind cares only for the ex­ter­nal beauty of the taber­na­cle (i.e. proper forms), know that you have not yet found the place of prayer and its blessed way is still far from you.

Know that in the midst of all spir­i­tual joy and con­so­la­tion, that it is still more nec­es­sary to serve God with de­vo­tion and fear (St. Nilus of Sinai, Texts on Prayer).

It is nat­ural for the mind to re­ject what is at hand and dream of some­thing else to come… to build fan­tasies and imag­in­ings about achieve­ments be­fore he has at­tained them. Such a man is in con­sid­er­able dan­ger of los­ing what he has and fail­ing into self-delu­sion and being de­prived of good sense. He be­comes only a dreamer and not a man of con­tin­ual prayer (i.e. a hesy­chast) (St. Gre­gory of Sinai, Texts on Com­mand­ments and Dog­mas).

If you are truly prac­tic­ing the con­tin­ual prayer of si­lence, hop­ing to be with God and you see some­thing sen­sory or spir­i­tual, within or with­out, be it even the image of Christ, or an angel, or some saint, or if an image of light per­vades your mind in no way ac­cept it… al­ways be dis­pleased with such im­ages, and keep your mind clear, with­out image or form… and you will suf­fer no harm. It has often hap­pened that such things, even when sent by God as a test be­fore vic­tory, have turned into harm for many… who have then done harm to oth­ers equally un­wise… lead­ing to pride and self-con­ceit.

For the fa­thers say that those who live rightly and are fault­less in their be­hav­ior with other men… who seek God with obe­di­ence, ques­tion­ing and wise hu­mil­ity… will al­ways be pro­tected from harm by the grace of Christ (St. Gre­gory of Sinai, In­struc­tions to Hesy­chasts).

The use of the Jesus Prayer out­side the hesy­chast method for un­ceas­ing prayer is to re­peat the prayer con­stantly and con­tin­u­ally, what­ever one is doing, with­out the em­ploy­ment of any par­tic­u­lar bod­ily pos­tures or breath­ing tech­niques. This is the way taught by St. Gre­gory Pala­mas in his short dis­course about how un­ceas­ing men­tal prayer is the duty of all Chris­tians. Any­one can do this, what­ever his oc­cu­pa­tion or po­si­tion in life. This also is shown in The Way of the Pil­grim.

The pur­pose and re­sults of this method of prayer are those gen­er­ally of all prayer: that men might be con­tin­u­ally united with God by un­ceas­ing re­mem­brance of His pres­ence and per­pet­ual in­vo­ca­tion of His name, so that one might al­ways serve Him and all men with the virtues of Christ and the fruits of the Spirit.

The third method of using the Jesus Prayer is to have it al­ways ready for mo­ments of temp­ta­tion. In this way, as St. John Cli­ma­cus has said, you can "flog your en­e­mies, i.e. the temp­ta­tions, with the name of Jesus for there is no stronger weapon in heaven or on earth" (The Lad­der of Di­vine As­cent). This method works best when one prac­tices the prayer with­out ceas­ing, join­ing "to every breath a sober in­vo­ca­tion of Jesus’ name" (Eva­grius of Pon­tus). When one prac­tices the con­tin­ual "prayer of the heart", and when the temp­ta­tions to sin enter the heart, they are met by the prayer and are de­feated by grace.

Man can­not live in this world with­out being tempted. When temp­ta­tion comes to a per­son, there are only three pos­si­ble re­sults. Ei­ther the per­son im­me­di­ately yields to the temp­ta­tion and sins, or he tries to ward off the temp­ta­tion by the power of his will, and is ul­ti­mately de­feated after great vex­a­tion and strife. Or else he fights off the temp­ta­tion by the power of Christ in his heart which is pre­sent only by prayer. This does not mean that he "prays the temp­ta­tion away". Or that God mirac­u­lously and mag­i­cally de­scends to de­liver him. It means rather that his soul is so filled with the grace and the power of God that the temp­ta­tion can have no ef­fect. It is in this sense that the Apos­tle John has writ­ten: "no one who abides in Christ sins" (1Ин. 3:6).

He who sins is of the devil… The rea­son the Son of God ap­peared was to de­stroy the works of the devil. No one born of God com­mits sins; for God’s na­ture abides in him, and he can­not sin for he is born of God. By this may be seen who are chil­dren of God, and who are chil­dren of the devil (1Ин. 3:8-10).

One be­comes a child of God, born of God in the Church through bap­tism. One con­tin­ues as a child of God and does not sin only by con­tin­ual prayer: the re­mem­brance of God, the abid­ing in Him, the call­ing upon His name with­out ceas­ing in the soul. The third use of the Jesus Prayer, like the first two, is to ac­com­plish this end: that man might not sin.

Or­tho­dox Church in Amer­ica