“Lo, who has not been startled a thousand times by the accents of this grave music, whose severe character, nevertheless, animates itself with the fires of passion and throws the soul, enlarged, into a religious reverie a thousand times more inebriating than the imposing voices of the great waters of which the Scriptures speak? Who has not tasted the charm of so many pieces sublime or original, stamped by the geniuses of the centuries past, who are no more and who have not left any other traces? Who has not shuddered at the simple planning of the Office of the Dead where the tender and the terrible are so admirably mixed? What Christian has ever been able to hear the Pascal chant of the Haec Dies without being tried with that vague sentiment of the infinite, as if Jehovah Himself was having His majestic voice heard? And who has not heard, during the solemnities of the Assumption of All Saints, an entire congregation making the sacred vaults of the roof resound with the inspired accents of the Gaudeamus, without his being brought back through the ages, to the epoch when the echoes of subterranean Rome resounded with this triumphant chant, when the Empire was painfully terminating its course, and the Church was starting its eternal destinies?” – Dom Gueranger, founder of Solesmes
“The musical tradition of the universal Church is a treasure of inestimable value, greater even than that of any other art”; also “sacred music is to be considered the more holy, the more closely connected it is with the liturgical action.” – Sacrosanctum Concilium
Catholic identity; chant is always and everywhere identified with the Catholic faith. Praise and worship / pop music makes the worship less Catholic, because it is taking something that is in the ‘world’ (with all its associations with entertainment, concerts, etc.) and importing into the Mass; which itself is ‘otherworldly’. Chant draws the senses in and elevates the mind towards the worship of God.
Chant captures the solemnness of the Mass
Popular hymns from the 70s/80s are superficial. Chant captures the difficult human emotions associated with deep sadness, suffering, longing for eternity, transcendent joy, the expectation of miracles, the profundity of salvation through death, or most other themes at the core of the Catholic faith. Chant is able to express meaning and sensibility of the life of Christ and the Church throughout the liturgical year, and is deeply beautiful in its complexity.
Chant is distinctively made for the Mass
The chant goes beyond the four hymns you can pick for Mass (known as the four-hymn sandwich). Gregorian chant developed alongside with the Mass as the Mass was eventually organised into a liturgical year. The essential musical structure of Mass emerged in the Middle Ages as the Entrance prayer became the Introit, and the Offertory and Psalm chants came into use. Because chant is attached so closely to the Mass as a part of its structure; chant is not only the music of the Mass, it is only the form of music that qualifies.
Chant lacks a beat-style, metered rhythm of modern music such as in rock, country, blues, etc. This is called plainsong. The rhythm is more free-flowing. There is an underlying pulse but it doesn’t cause you to want to tap your toe or dance. What it does do is lift the senses, to take us out of time and reflect on eternal things. In contrast, music with beats keeps us grounded and internal.
Past Popes (notably Pope St. Pius X) proclaimed the importance of Gregorian chant and polyphony as the official music of the Church’s liturgy. Para 116 of SC affirmed chant is “especially suited to the Roman liturgy” and “other things being equal, it should be given pride of place in liturgical services.”
Chant is humble
Praise and Worship tends to concentrate all attention to the performers. The bands are featured as they do all the singing, and the singing style naturally elicits egoism. Chant does not seek to put the talent of any individual singer on exhibit. Scholas serve the Mass, making the chant all about community prayer. The ego is buried, as St. John the Baptist said “Let me decrease and let him increase in me.”
Any priest from Africa could come to any parish in another country and quickly pick up on the Mass ordinaries and propers. The ordinary settings of the Kyrie, Gloria, Credo, Sanctus and Agnus are worldwide settings in which no national culture in particular is embedded in its sound and feeling. This is true of the propers of the Mass (Introit, Gradual, Alleluia, Offertory, Communion). The Catholic Church is a universal church and universal liturgical forms are required to reflect its global unity. Furthermore, its music in Mass must transcend time, place and cultural character of its people.
Musicians want a challenge
Chant has centuries of daunting and difficult repertoire and best serves to organize and measure the best of musical talent in the church. Postconciliar practice hardly challenges musicians and does nothing to inspire serious musical accomplishment.
The Motu Proprio: Summorum Pontificum
The Summorum Pontificum granted greater freedom to priests to use the Tridentine liturgy in its 1962 form. It provides the impetus for the revival of Gregorian chant. Although the Tridentine is more associated with the chant, the Novus Ordo and both forms of the Mass use the Graduale Romanum as the normative form of music. The introits, communions, and chants are the same in both forms.