In the Roman rite, however, the chanting of the Holy Book means more than merely singing a paragraph from the Bible. The majority of the texts chosen for liturgical chant entered the liturgy as a result of three or four centuries of theological reflection. The material selected for chanting in the liturgy is a particular manifestation of authentic Christian theology. The connection between a text chosen for chanting, and a given solemnity or liturgical season, is based upon the contemplation and interpretation of generations of Church Fathers. Feasts were interpreted by the explanation of biblical verses and, vice versa, the explanation of the biblical verses took place in the liturgical context of feasts.
For instance, when Psalm 2 was adopted in the Christmas liturgy, its background was a deep understanding of Christmas; the mystery found its appropriate expression in Psalm 2. On the other hand, the precondition of such an adaptation was the Christological understanding of Psalm 2, which included its connection with the mystery of the Nativity. The context of the Christmas feast is deficient without the inclusion of Psalm 2, and the interpretation of Psalm 2 is deficient without the dogmatic content concerning the Second Divine Person. Psalm 2 (the Introit and Alleluia verse of the Midnight Mass) is closely related to St. Paul’s Letter to the Hebrews (Epistle of the Third Mass of Christmas Day) and to St. John’s Prologue (the Gospel of the Third Mass). Anyone who is familiar with the liturgy of the praying Church is aware of the importance of Psalms 18, 24, 79, and 84 in the spiritual message of the Advent season, an importance not inferior to that of the lections and prayers. These psalms, as they occur and recur, pray into the mind precisely that content of the Advent season, as well as its mystery, which is given by the praying Church — and not by individuals. The responsorial psalm is one element in this process, but not a self-sufficient one. The singer and the listener are influenced in a different way by the main verses chosen from the psalm and performed in a melodious way, than by a longer section of the psalm.
Therefore, he who removes the Proper chants from the Mass of the day or the season (e.g., Advent or Lent), mutilates the liturgy and diminishes the content of the feast, by depriving the praying Church of an excellent means of fully understanding the feast being celebrated. It is totally false to suppose that the full content of a given liturgical celebration can be adequately conveyed by readings and prayers alone, while the chanted texts are omitted. What these biblical texts transmit cannot be replaced or even approximated by poetic songs and hymns, as precious as they may be. And even if such texts would remain close to the biblical words, they remain human words, taken out of the biblical (i.e. inspired) context. I dare say that whoever removes the proper chants, mutilates and diminishes the theology as well, which lives not only in manuals and textbooks, but also in the spirituality of the praying Church, the Ecclesia orans.
Laszlo Dobszay, The Bugnini-Liturgy and the Reform of the Reform (2003)