The Jesus Prayer, also called the prayer of the heart by some Church Fathers, is a short, simple prayer that has been widely used, taught and discussed throughout the history of Eastern Christianity. The exact words of the prayer have varied, from a simple form such as "Lord, have mercy" to the more extended "Lord Jesus Christ, Son of God, have mercy on me, a sinner."
The text of this prayer is based on various accounts in the Gospels, such as Peter crying out as he sank into the sea, "Lord, save me." To the publican's cry in the Temple, "God, have mercy on me, a sinner". In succinct form, the prayer acknowledges Christ's lordship and confesses the sinfulness of the person praying. The full form is sometimes described as being implicitly Trinitarian as well: the Son is addressed explicitly; addressing him as Son acknowledges the Father; and according to Saint Paul's writings in the New Testament, no one can call Christ "Lord" without the aid of the Holy Spirit.
The prayer is often said or prayed repeatedly, sometimes with the aid of a prayer rope. As such, is used as a means of concentration, as a means of bringing about mental focus and eventually as a way to "internalize" the prayer, so that one is praying constantly. This is one way to follow Saint Paul's exhortation to the Thessalonians to "pray without ceasing". The use of the Jesus Prayer in this way is the subject of the Russian classic The Way of a Pilgrim.
