The Ladder of Divine Ascent of St. John Climacus

Lord Jesus Christ, Son of God, have mercy on me, the sinner.

The Jesus Prayer, also called the Prayer of the Heart, the Prayer of a Single Thought, or simply The Prayer, 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 an extended form:

“Lord Jesus Christ, Son of God, have mercy on me, the sinner.”

The Jesus Prayer is not limited only to monastic life or to clergy. All members of the Christian Church are advised to practice this prayer, laypeople and clergy, men, women and children. The prayer is said or prayed repeatedly, often with the aid of a prayer rope (Russian: chotki; Greek: komvoskini), which is a cord, usually woolen, tied with many knots. The person saying the prayer says one repetition for each knot. The prayer rope is “a tool of prayer”. The use of the prayer rope, however, is not compulsory.

Its practitioner’s ultimate goal is to “internalize” the prayer, so that one is praying unceasingly there-by accomplishing Saint Paul’s exhortation to the Thessalonians to “pray without ceasing” (I Thessalonians 5:17). The use of the Jesus Prayer is recommended in the Ladder of Divine Ascent of St. John Climacus (c. 523–606) and in the work of St. Hesychios the Priest (ca. 8th century), Pros Theodoulon, found in the first volume of the Philokalia. The use of the Jesus Prayer in this way is the subject of the classic The Way of a Pilgrim.

Text above compiled from articles “Jesus Prayer” on Wikipedia and OrthodoxWiki.