Musical Advent Calendar, 2011 edition: Day 24

I was brought up Catholic. I spent countless Sunday mornings in church and attending Sunday school (technically called Catechism, even though since Vatican II, the Catechism has rather gone by the wayside). I have to admit, even though I'm sort of lapsed, I still feel the pull to Mass on Christmas Eve. And Christmas Eve Mass always--in whatever church I was in--included this song. It still calls up indefinable emotions for me.