Sacred music, being a complementary part of the solemn liturgy, participates in the general scope of the liturgy, which is the glory of God and the sanctification of the faithful… and since its principal office is to clothe with suitable melody the liturgical text proposed for the understanding of the faithful, its proper aim is to add greater efficacy to the text, in order that through it the faithful may be the more easily moved to devotion.
Pope St. Pius X