It is entirely proper to set prayers to music, and the
friends are free to sing prayers in unison. Indeed, assuming that the music is
appropriate and that the believers do not make a ritual out of it, it is highly
praiseworthy for choirs to sing appropriate verses revealed be Bahá'u'lláh and
the Master...
We would assume also that the friends will always keep in
mind that whether read, chanted or sung, prayers should be uttered with proper
sense of reverence.
- The Universal House of Justice (From a letter to the
National Spiritual Assembly of Australia, February 6, 1973; Compilation: ‘Lights
of Guidance’)