The words:
O magnum mysterium, et admirable sacramentum, ut animalia viderent Dominum natum, jacentum in praesepio!
Beata Virgo, cujus viscera meruerunt portare Dominum Christum. Alleluia!
O great mystery, and wondrous sacrament, that animals should see the newborn Lord, lying in their manger!
Blessed is the Virgin whose womb was worthy to bear the Lord Jesus Christ. Alleluia!
This is sung by the University of Santo Tomas Alumni Singers directed by Allan Diona Sims. My understanding is that this performance is in 2006 at the Hollywood Choir Festival, at the Hollywood United Methodist Church across from the Kodak Theater.
This is so lovely it just makes me weep.