Ordinary Form·Introductory Rites
Kyrie
'Lord, have mercy' — a sung acclamation to Christ.
What happens
Unless the Kyrie has already been included in the Penitential Act, it follows directly. Each acclamation ('Lord, have mercy… Christ, have mercy… Lord, have mercy') is ordinarily said twice, though the number may vary depending on the musical setting.
Why it happens
The Kyrie is a chant by which the faithful acclaim the Lord and implore his mercy. Because it is a song, it is ordinarily to be sung by all, involving the people and the choir or cantor.
Sources
- GIRM §52
- Order of Mass n. 7