This divine prayer, which consists of the invocation of the name of our Savior Jesus Christ, specifically “Lord Jesus Christ, Son of God, have mercy on me,” is simultaneously a prayer, a devotion, and a confession of faith.
This prayer bestows the Holy Spirit, it transmits divine gifts, it purifies the heart, it banishes the demons, it makes Jesus Christ dwell within us, it is a source of spiritual understanding and divine awareness, it liberates us from sins, it is a cure for both our souls and bodies, it imparts divine enlightenment, it is a fountain gushing forth God’s mercy, and it confers divine revelations and mystical knowledge of God to them who have humility.
It is the only thing that affords salvation, because it contains the salvific name of our God, which is the only name that has been given to us [for salvation], that is the name of Jesus Christ the Son of God, and it is not possible for us to be saved through any other name, as the Apostle Peter indicates: “Nor is there salvation in any other, for there is no other name under heaven given among men by which we must be saved” (Acts 4:12).
It is primarily a prayer, because through it we seek God’s mercy. It is also a devotion, because we surrender ourselves to Christ when we invoke His name. Furthermore it is a confession, because when the Apostle Peter confessed this name, “You are the Christ, the Son of the living God,” he was praised by the Lord thus, “Jesus then answered and said to him, ‘Blessed are you Simon Bar-Jonah, for flesh and blood has not revealed this to you, but My Father who is in heaven’” (Mt. 16:16-17). It also imparts the Holy Spirit, because no one can refer to Jesus as “the Lord” without the Holy Spirit: “No one can say that Jesus is Lord except by the Holy Spirit” (1 Cor. 12:3).
Additionally, it is the transmitter of divine gifts, since it was on account of this confession that Christ promised the Apostle Peter that He would give him the keys to the Kingdom of Heaven: “And I will give you the keys of the kingdom of heaven,”(Mt. 16:19).
It is purification of the heart, because it sees and calls upon God Who purifies the person beholding Him. It expels the demons because with the name of Jesus Christ all the demons were and continue to be expelled. It is the dwelling of Christ within us, because when we bring Christ to mind, He is within us, and with this memory He dwells in us and fills us with joy, just as the Prophet David describes in the Psalms, “I remembered God and I was gladdened” (Ps. 76:4).
Furthermore, it is a fountain of spiritual understanding and contemplation because Christ is the treasury of all wisdom and knowledge: “Of Christ, Whom are hidden all the treasures of wisdom and knowledge” (Col. 2:3), and He transmits these to them in whom He dwells. It is liberation from sins because on account of this confession the Lord said to Peter, “And whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven” (Mt. 16:9).
It is the cure of our souls and bodies because the Apostle Peter said, “‘In the name of Jesus Christ of Nazareth, rise up and walk,’ and immediately the lame man “stood and walked” (Acts 3:6-8); and elsewhere when he said, “‘Aeneas, Jesus the Christ heals you. Arise and make your bed.’ Then he [Aeneas] arose immediately” (Acts 9:34). It is the issuer of divine enlightenment because Christ is the true light: “He is the true Light who gives light to every man coming into the world” (Jn. 1:9), and He transmits His brilliance and grace to them who call upon Him, as it is stated in the Psalms: “And let the brightness of the Lord our God be upon us” (Ps. 89:17). The Lord likewise confirms: “I am the light of the world. He who follows Me shall not walk in darkness, but have the light of life” (Jn. 8:12).
It is moreover a fountain of God’s mercy because we plead for mercy, and the merciful Lord shows His compassion to all them who call upon Him, “The Lord is nigh unto all that call upon Him” (Ps. 144:18) and He quickly administers justice to all them who call upon Him: “Shall God not avenge His own elect who cry out day and night to Him, though He bears long with them? I tell you that He will avenge them speedily” (Lk. 18:7).
This is the marker of our faith, since we are called and are in deed Christians, and it also serves as testimony that we are of God. For the Evangelist states: “Every spirit that confesses that Jesus Christ has come in the flesh is of God” (1Jn. 4:3), as we have already mentioned, and whoever does not confess this is not from God; whoever does not confess Jesus Christ is from the antichrist.
This is why all we faithful must ceaselessly confess this name: in order to profess and proclaim our faith; on account of the love of our Lord Jesus Christ, from which love nothing must ever separate us: “What shall separate us from the love of Christ? ... neither death nor life, nor angels nor principalities nor powers, nor things present nor things to come, nor height nor depth, nor any other created thing shall be able to separate us from the love of God which is in Christ Jesus our Lord” (Rom. 8:35); and because the name of Christ bestows grace, forgiveness, redemption, healing, sanctification, enlightenment, and above all salvation. Because with this divine name the Apostles accomplished and taught great and wonderful things. And the divine Evangelist says, “these things are written so that you may believe that Jesus is the Christ, the Son of God”–behold the faith! “And that believing you may have life in His name”—behold the salvation and the life! (Jn. 20:31).
St. Symeon Archbishop of Thessaloniki
https://www.stnektariosmonastery.org/en/index.php