Music has been used to ward off evil spirits, to communicate with God, and to appease the angry gods. Others have used it to heal illness and felt, like Pythagorus, that each note affected a different part of the body, a different organ. All religions have used music as part of their ceremonies. With the Aztecs, the chief function was to obtain mystical communication with a particular god. We're close to the same ritual when we go to a place of worship to sing and pray.
Music brings people together in a feeling of togetherness.
This is a deeply fundamental spiritual quality that is diminishing as we become more and more earthbound and materialistic. Schools are unwittingly doing a grave disservice to children by removing music and art from their curriculum to make way for computers. The smartest educators would see that there needs to be a balance between left and right brain activities, between technology and the arts, between the head and the heart. In the Middle Ages, cathedrals were built to classical music played by full orchestras in the belief that the stones held the notes and healings could take place within the walls. Families came from all over the countryside with a reverence to watch the church being built and listen to the music.