~ Johannes Sebastian Bach
"Herz und Mund und Tat und Leben" means "Heart and Mouth and Deed and Life," which seems like a lovely way to describe this song, the 10th movement of Bach's Herz und Mund und Tat und Leben cantata. It's also known as Jesu, Joy of Man's Desiring.
For more info on J.S. Bach
For more info on Sissel, who sings in the video