ANY PRIESTS BELIEVE the Kyrie Eleison (“Lord, have mercy”) to be part of the Penitential Rite, but that’s incorrect. The only time the Kyrie is part of the Penitential Rite is when the priest chooses Option C 1 — the one that begins:
“You were sent to heal the contrite of heart: Lord, have mercy … etc.”
The first proof is GIRM #46. Notice how the Kyrie is distinguished from the Penitential Act:
The rites that precede the Liturgy of the Word, namely, the Entrance, the Greeting, the Penitential Act, the Kyrie, the Gloria in excelsis (Glory to God in the highest) and Collect, have the character of a beginning, an introduction, and a preparation.
The second proof is GIRM #52. Obviously something that comes after the Penitential Rite is not part of that Rite:
After the Penitential Act, the Kyrie, eleison (Lord, have mercy), is always begun, unless it has already been part of the Penitential Act.
The third proof is the Ceremonial of Bishops #255, which says on Ash Wednesday:
The introductory rites of the Mass and, as circumstances suggest, also the Kyrie are omitted, and the bishop immediately says the opening prayer.
The fourth proof is GIRM #125. The Kyrie is once again distinguished from the Penitential Act:
The Penitential Act follows. After this, the Kyrie is sung or said, in accordance with the rubrics (cf. no. 52).
The fifth proof is the Roman Missal, Third Edition, which says for Ash Wednesday (Stational) and Palm Sunday:
Omitting the Introductory Rites and, if appropriate, the Kyrie, he says the Collect of the Mass, and then continues the Mass in the usual way.
WHY, THEN, is the Kyrie so often wrongly omitted? Especially at Weddings (Nuptial Mass) the Kyrie is wrongly omitted. I don’t know the answer, but my guess is that most priests believe the Kyrie is part of the Penitential Act.
See also Andrew’s treatment.
More opinions on this matter are given by the Bishop’s Committee on the Liturgy.
NOTES FROM THIS ARTICLE:
1 If “Option B” is used, the Kyrie is still said, even though Option B begins with Miserére nostri, Dómine (“Have mercy on us, O Lord”).