“Lord, have mercy,” “Kyrie Eleison” in Greek, is a very early brief prayer for divine mercy. It has its origin as a response to a litany of prayer intentions announced by deacons in the Eastern rite churches. The Kyrie litany was introduced into the Roman liturgy toward the end of the fifth century by Pope Gelasius I, who was a Greek from Sicily. His intention was to replace the older and lengthy intercessory prayers that occurred at the end of the liturgy of the word. A remnant of these lengthy intercessory prayers can still be found in our liturgy of Good Friday. Later Pope Gregory the Great, who had a well-known desire to shorten the liturgy, eliminated the naming of the intentions, leaving only the acclamations Kyrie eleison, Christe eleison, Kyrie eleison.
This short litany of acclamations is today found, not after the liturgy of the word, but as one of the optional forms of the penitential rite at the beginning of the liturgy. It may be sung or spoken either in English or in Greek. Indeed, since it may be sung or spoken in Greek, the Kyrie is the only text of the liturgy that is in the ancient language of the gospels. These acclamations are addressed to the Lord Jesus, and not to the Trinity, as one might be led to think. Instructions on the proper celebration of the liturgy explain that after the act of penitence the Kyrie is always begun, unless it has already been included as a part of the act of penitence. Since it is a chant by which people acclaim the Lord and implore divine mercy, it is ordinarily done by all, that is, by the people and with the choir or cantor having a part in it.
Such short prayers as “Lord, have mercy” have a unique power, but they are also open to a special danger: they can be easily spoken without passing through the heart. The Kyrie is a very ancient cry for mercy in our liturgy, and so deserves our careful attention as we utter it. In the gospels we see that it is the humble prayer of the two blind men begging for light; it is the tumultuous imploring of Bartimaeus on the road to Jericho, begging for sight; it is the audacious prayer of the Canaanite woman for her little girl. So the litany of the Kyrie is the litany of human misery imploring the mercy of Jesus on the roads of his public ministry. Can it not remain the litany of our misery on the road of our life?
The German liturgist Fr. Balthasar Fischer comments on the Kyrie: “To reflect on this prayer is, above all, to consider what it means to call upon Christ as Lord. The Greek form ‘Kyrie’ is the word chosen by the Greek translators of the Old Testament as the equivalent of the Hebrew word for God. When addressed to Christ, the word amounts to a grateful, laudatory confession of the divinity of him who by dying conquered death; it was a confession that could cost people their lives during the early persecutions. We find, then, that even so very brief a prayer as this follows the general rule that praise and thanksgiving come first and the petition flows from these. Because you are our Lord, who passed victoriously through death to life, therefore we pray you: Have mercy on us and on the whole world. The petition means more than ‘Help us!’ It means: ‘Take all of us with you on your journey through death to life.’”