What are the concrete attributes of sacred music? The Catechism (CCC 1157) teaches that sacred music fulfills its task according to three criteria: 1) the beauty expressive of prayer, 2) the unanimous participation of the assembly at the designated moments, and 3) the solemn character of the celebration. All three criteria link sacred music intimately to the work of Christ in the liturgy and in our hearts.
The beauty expressive of prayer. As we have seen, sacred music is the Church’s liturgical prayer in sung form. When we hear sacred music, we hear prayer. We hear the liturgy itself. In the Mass, we hear that most beautiful of prayers: Christ’s prayer of self-offering to the Father. Music can express any number of things; but sacred music expresses something utterly unique: the saving and sacrificial prayer of Christ and the Church in the liturgy.
Unanimous participation. As I addressed in previous articles on the new English translation of the Mass, liturgical participation is primarily participation with and in Christ Himself, rooted by the deep interior participation of each person. Sacred music powerfully aids us in this union of the heart and mind with whatever liturgical action is taking place exteriorly. “Unanimous” means “of one mind/soul”; thus sacred music aims to unite us all to the soul of Christ in perfect love for the Father at every step of the Mass.
Solemn character. In the sacred liturgy, Christ our Lord performs the work of our redemption through sacramental signs. The liturgy then is a solemn experience, and therefore sacred music bears this character. Far from meaning cold, unfeeling, or aloof, the solemn character of sacred music refers to its earnest, intense, and festive focus on the great Mystery which it serves: Christ’s redemptive and transformative love for His Church. — from “Singing the Mass”