What is the full lyrics of the song Si deus me relinquit? During the 1:42 of the song there is some choir (priests?) singing in the background.
But I couldn't find out what they actually singing about.
Where can I found the lyrics of this song with the choir part included?
It seems to say

Agnus Dei qui tollis peccata mundi
(eng: Lamb of God, you who take away the sins of the world)

recalling this other music.