Many believe it is this prayer.
For many Christians around the world, the Our Father and Hail Mary stand as the basic pillars of their prayer life. But after those two traditional prayers, there stands one biblical prayer that is equally popular among a variety of Christians.
It is called the “Jesus Prayer” and many believe it is one of the most popular Christian prayers of all time.
It is an ancient prayer that was largely influenced by the Desert Fathers of Egypt. An early form of the prayer is first mentioned by St. Diadochos of Photiki, an ascetic monk in Greece during the early 5th century. The prayer was later featured in a collection of influential spiritual writings called The Philokalia that became a foundational book in Eastern Christianity.
For many centuries the Jesus Prayer was found only in Orthodox churches, particularly in Russia where a spiritual classic, The Way of the Pilgrim, popularized it during the 19th century.
Recently the prayer has received a renewed interest among Christians across all denominations and countless Christians have made it a central part of their spirituality.
The Catechism of the Catholic Church devotes a few paragraphs explaining the Jesus Prayer.
2667 This simple invocation of faith developed in the tradition of prayer under many forms in East and West. The most usual formulation, transmitted by the spiritual writers of the Sinai, Syria, and Mt. Athos, is the invocation, “Lord Jesus Christ, Son of God, have mercy on us sinners.” It combines the Christological hymn of Philippians 2:6-11 with the cry of the publican and the blind men begging for light. By it the heart is opened to human wretchedness and the Savior’s mercy.
2668 The invocation of the holy name of Jesus is the simplest way of praying always. When the holy name is repeated often by a humbly attentive heart, the prayer is not lost by heaping up empty phrases, but holds fast to the word and “brings forth fruit with patience.” This prayer is possible ‘at all times’ because it is not one occupation among others but the only occupation: that of loving God, which animates and transfigures every action in Christ Jesus.
It is a powerful prayer, one that is focused on reciting the name of Jesus. Often this prayer is recited while holding a chotki (a type of prayer rope) to count the number of times the prayer is said.
Connected to this prayer is a breathing technique where the words are said to synchronize with the body. Here is one description of the exercise by an Orthodox bishop.
Often the first part, “Lord Jesus Christ, Son of God,” is said while drawing in the breath, and the second part, “have mercy on me a sinner,” while breathing out. Other methods are possible. The recitation of the Prayer may also be synchronized with the beating of the heart.
It is a beautiful prayer, one that is focused on Jesus and his mercy.
Here are several different ways the prayer can be prayed.
Lord Jesus Christ, have mercy on me!
Lord Jesus Christ, Son of God, have mercy on me, a sinner.
Lord Jesus Christ, Son of God, have mercy on us sinners.
Lord Jesus, have mercy!