1. The first principle of the discipline of the arts is that an art is not good in itself -- "ars gratia artis" is a wrong concept, offensive to the human spirit. Art MUST be subjected to God and His Law. In the words of the glorious Pope Pacelli, one can sense the seed of disobedience which would cause so much harm to the Church in a few years:
...we are aware of the fact that during recent years some artists, gravely offending against Christian piety, have dared to bring into churches works devoid of any religious inspiration and completely at variance with the right rules of art. They try to justify this deplorable conduct by plausible- looking arguments which they claim are based on the nature and character of art itself. They go on to say that artistic inspiration is free and that it is wrong to impose upon it laws and standards extraneous to art, whether they are religious or moral, since such rules seriously hurt the dignity of art and place bonds and shackles on the activity of an inspired artist.
The ordination and direction of man to his ultimate end - which is God - by absolute and necessary law based on the nature and the infinite perfection of God Himself is so solid that not even God could exempt anyone from it. This eternal and unchangeable law commands that man himself and all his actions should manifest and imitate, so far as possible, God's infinite perfection for the praise and glory of the Creator. Since man is born to attain this supreme end, he ought to conform himself and through his actions direct all powers of his body and his soul, rightly ordered among themselves and duly subjected to the end they are meant to attain, to the divine Model. Therefore even art and works of art must be judged in the light of their conformity and concord with man's last end.
Art certainly must be listed among the noblest manifestations of human genius. Its purpose is to express in human works the infinite divine beauty of which it is, as it were, the reflection. Hence that outworn dictum "art for art's sake" entirely neglects the end for which every creature is made. Some people wrongly assert that art should be exempted entirely from every rule which does not spring from art itself. Thus this dictum either has no worth at all or is gravely offensive to God Himself, the Creator and Ultimate End.
2. Art must, in principle, be ordered by Divine Law. Religious Art must, furthermore, be practiced only by artists who are truly inspired by Faith and Love of God:
...religious art is even more closely bound to God and the promotion of His praise and glory, because its only purpose is to give the faithful the greatest aid in turning their minds piously to God through the works it directs to their senses of sight and hearing. Consequently the artist who does not profess the truths of the faith or who strays far from God in his attitude or conduct should never turn his hand to religious art. He lacks, as it were, that inward eye with which he might see what God's majesty and His worship demand. Nor can he hope that his works, devoid of religion as they are, will ever really breathe the piety and faith that befit God's temple and His holiness, even though they may show him to be an expert artist who is endowed with visible talent. Thus he cannot hope that his works will be worthy of admission into the sacred buildings of the Church, the guardian and arbiter of religious life.
But the artist who is firm in his faith and leads a life worthy of a Christian, who is motivated by the love of God and reverently uses the powers the Creator has given him, expresses and manifests the truths he holds and the piety he possesses so skillfully, beautifully and pleasingly in colors and lines or sounds and harmonies that this sacred labor of art is an act of worship and religion for him. It also effectively arouses and inspires people to profess the faith and cultivate piety.
These laws and standards for religious art apply in a stricter and holier way to acred music because sacred music enters more intimately into divine worship than many other liberal arts, such as architecture, painting and sculpture. These last serve to prepare a worthy setting for the sacred ceremonies. Sacred music, however, has an important place in the actual performance of the sacred ceremonies and rites themselves.
4. The great principle of Sacred Music is:
...to prevent whatever might be unbecoming to sacred worship or anything that might distract the faithful in attendance from lifting their minds up to God from entering into sacred music, which is the servant, as it were, of the sacred liturgy.
5.Sacred Music is INSEPARABLE from the Most Holy Sacrifice:
It is easy to infer from what has just been said that the dignity and force of sacred music are greater the closer sacred music itself approaches to the supreme act of Christian worship, the Eucharistic sacrifice of the altar. There can be nothing more exalted or sublime than its function of accompanying with beautiful sound the voice of the priest offering up the Divine Victim, answering him joyfully with the people who are present and enhancing the whole liturgical ceremony with its noble art.
6. Popular Religious Music should be given due recognition, but it is strictly ALITURGICAL, that is, it is not proper for the Sacrifice:
We must also hold in honor that music which is not primarily a part of the sacred liturgy, but which by its power and purpose greatly aids religion. This music is therefore rightly called "religious" music. The Church has possessed such music from the beginning and it has developed happily under the Church's auspices. As experience shows, it can exercise great and salutary force and power on the souls of the faithful, both when it is used in churches during non-liturgical services and ceremonies, or when it is used outside churches at various solemnities and celebrations.
The tunes of these hymns, which are often sung in the language of the people, are memorized with almost no effort or labor. The mind grasps the words and the music. They are frequently repeated and completely understood. Hence even boys and girls, learning these sacred hymns at a tender age, are greatly helped by them to know, appreciate and memorize the truths of the faith. Therefore they also serve as a sort of catechism. These religious hymns bring pure and chaste joy to young people and adults during times of recreation. They give a kind of religious grandeur to their more solemn assemblies and gatherings. They bring pious joy, sweet consolation and spiritual progress to Christian families themselves. Hence these popular religious hymns are of great help to the Catholic apostolate and should be carefully cultivated and promoted.
7. Sacred Music must be not only beautiful, but must serve to the Apostolic Mission of the Church:
Therefore when We praised the manifold power and the apostolic effectiveness of acred music, We spoke of something that can be a source of great joy and solace to all who have in any way dedicated themselves to its study and practice. All who use the art they possess to compose such musical compositions, to teach them or to perform them by singing or using musical instruments, undoubtedly exercise in many ways a true and genuine apostolate. They will receive from Christ the Lord the generous rewards and honors of apostles for the work they have done so faithfully.