“Lord Jesus Christ, Son of God, have mercy on me, the sinner.”
Κύριε Ἰησοῦ Χριστέ, Υἱὲ τοῦ Θεοῦ, ἐλέησόν με τὸν ἁμαρτωλόν
The Jesus Prayer is a profound mystical prayer and personal ascetical practice taken from Hesychasm and is esteemed by the spiritual fathers of the tradition found in the Philokalia. This prayer is a method that opens the heart bringing about what is known as the prayer of the heart which is the unceasing prayer the apostle Paul advocates in 1 Thessalonians 5:17.
The words of the Jesus prayer are taken from the parable of the Publican and the Pharisee. In humility the Publicans prays "Lord have mercy on me, the sinner" Luke 18: 10-14.
Used with a prayer rope it may be accompanied by prostrations and the sign of the cross as a means of finding humility. Monastics often have long sessions praying this prayer many hundreds of times each night with the ultimate goal to "internalize" the prayer, so that one is praying unceasingly. After a time, the Jesus Prayer enters into the heart, so that it is no longer recited by a deliberate effort, but recites itself spontaneously.
The power of the name of Jesus transforms the one who prays. It is often accompanied by breathing in during the first part, “Lord Jesus Christ, Son of God” and then with the breath out saying, “have mercy on me, the sinner.”