"Among the many signs and symbols used by the Church to celebrate its faith, music is of preeminent importance. As sacred song united to words, it forms a necessary or integral part of the solemn liturgy. Yet the function of music is ministerial; it must serve and never dominate. Music should assist the assembled believers to express and share the gift of faith that is within them and to nourish and strengthen their interior commitment of faith. It should heighten the texts so that they speak more fully and more effectively. The quality of joy and enthusiasm which music adds to community worship cannot be gained in any other way. It imparts a sense of unity to the congregation and sets the appropriate tone for a particular celebration." -
The Liturgy Documents, Music in Catholic Worship Document, The Place of Music in the Celebration, paragraph #23