The Jesus Prayer: Lord Jesus Christ, Son of God, have mercy on me (a sinner), is a prayer of the heart to help us pray without ceasing. Even when shortened to Lord have mercy, (Divine Liturgy, or private prayer) it brims with bountiful blessings! The juicy root-words for ‘mercy’ in Greek and Hebrew, are jam-packed with more meaning!
…“Lord, Have Mercy.” The true meaning behind this short prayer often gets lost in English, because the word “mercy” takes on a connotation of “justice or acquittal.” This is not the tenor of the prayer that we say in the Divine Liturgy. We aren’t saying: “Lord…don’t convict me and send me to the outer darkness!” The Greek word that is used for “mercy” comes from “eleos”, which is the same root word as the word for “oil” which is used to sooth or to heal. The Hebrew word for “mercy” comes from “hesed” which means “steadfast love.” In the Church, when we say “Lord have mercy”, we are literally saying over and over and over: “Lord…soothe me…and show me your steadfast love! ...“Show us your healing love O Lord”! ~ Fr. Gabriel Bilas (pravmir.com)
If you feel sweetness or compunction at some word of your prayer, dwell on it; for then our guardian angel is praying with us. ~ St. John Climacus (Ladder of Divine Ascent)