The practice aims at "prayer of the heart"—moving beyond mental recitation to continuous remembrance of God's presence. Early stages involve conscious repetition; with practice, the prayer becomes "self-acting," continuing involuntarily like breathing.
Hesychast monks of Mount Athos developed techniques: sitting in specific postures, breathing rhythmically, directing attention to the heart. This physical dimension distinguishes it from purely mental prayer, engaging body-mind-spirit unity.
The prayer's first half invokes Christ's presence; the second acknowledges human need and dependence. It combines faith (Lord Jesus Christ, Son of God) with humility (have mercy on me, a sinner), theology with spiritual need.
The practice influenced Russian spirituality profoundly, described in The Way of a Pilgrim, where a wanderer learns continuous prayer. It offers a simple, portable practice for maintaining consciousness of divine presence amid daily activities.
The prayer demonstrates how repetitive practices across traditions—japa, dhikr, nembutsu—use similar principles to cultivate unceasing awareness.
Source
Eastern Orthodox Tradition - Hesychasm