Breath is at the heart of singing, for it is the singer's breath, voice, and spirit that produce the song.  Those who chant or sing spiritual songs tell of entering into a deeper level of worship, understanding, freedom, and joy when they sing, which deepens their faith. . . . . And just as breath is not only inside us but comes out of us as well, the breath of God that inspires us can come forth and move others.  We have all felt joy and freedom and spirit come bursting out of a singer's song.  We respond not just to notes or melody, but to the passion in both, to the life that is in the music.

-- Joanna Laufer and Kenneth S. Lewis
(Inspired Lives:  Exploring the Role of Faith and Spirituality in the Lives of Extraordinary People)