Here is a list of resources for those who wish to follow the call of the Second Vatican Council to ensure that chant has primacy of place, and that the faithful are singing the Propers.
The Church acknowledges Gregorian Chant as especially suited to the Roman Liturgy. Therefore, other things being equal, it should be given pride of place in liturgical services (Sacrosanctum Concilium).
The General Instruction of the Roman Missal, in setting out the norms for the celebration of Mass reiterates this last point of the Second Vatican Council:
The main place should be given, all things being equal, to Gregorian chant, as being proper to the Roman Liturgy (General Instruction of the Roman Missal)
One of most beloved Popes of our time, Blessed John Paul II discusses this in his own teachings on chant in the Mass:
With regard to compositions of liturgical music, I make my own the "general rule" that St Pius X formulated in these words: "The more closely a composition for church approaches in its movement, inspiration and savor the Gregorian melodic form, the more sacred and liturgical it becomes; and the more out of harmony it is with that supreme model, the less worthy it is of the temple". It is not, of course, a question of imitating Gregorian chant but rather of ensuring that new compositions are imbued with the same spirit that inspired and little by little came to shape it (Blessed John Paul II: Chirograph for the Centenary of Tra le sollecitudini).
Our Holy Father Emeritus, Pope Benedict XVI, has made known his own teaching on the importance of Gregorian chant to the sacred liturgy:
While respecting various styles and different and highly praiseworthy traditions, I desire, in accordance with the request advanced by the Synod Fathers, that Gregorian chant be suitably esteemed and employed as the chant proper to the Roman liturgy (Benedict XVI: Sacramentum caritatis).
It important to note that the fathers of the Second Vatican Council desired the Faithful to sing the Propers in Mass:
It is desirable that the assembly of the faithful should participate in the songs of the Proper as much as possible, especially through simple responses and other suitable settings (Musicam Sacram).
This can also be seen in the writings of the same Consilium which produced the Mass of Paul VI immediately after it was promulgated by the Holy Father:
Query: Many have inquired whether the rule still applies that appears in the Instruction on sacred music and the liturgy, 3 Sept. 1958, no. 33: “In low Masses religious songs of the people may be sung by the congregation, without prejudice, however, to the principle that they be entirely consistent with the particular parts of the Mass.”
Reply: That rule has been superseded. What must be sung is the Mass, its Ordinary and Proper, not “something,” no matter how consistent, that is imposed on the Mass. Because the liturgical service is one, it has only one countenance, one motif, one voice, the voice of the Church. To continue to replace the texts of the Mass being celebrated with motets that are reverent and devout, yet out of keeping with the Mass of the day (for example, the Lauda Sion on a saint’s feast) amounts to continuing an unacceptable ambiguity: it is to cheat the people. Liturgical song involves not mere melody, but words, text, thought, and the sentiments that the poetry and music contain. Thus texts must be those of the Mass, not others, and singing means singing the Mass not just singing at Mass (Notitiae 5 (1969) 406)(re-printed in the Bishops' Committee on the Liturgy's BCL Newsletter, August-September 1993).
The preference for use of the Propers was highlighted by the United States Conference of Catholic Bishops in 2007:
*Proper antiphons from the liturgical books are to be esteemed and used especially because they are the very voice of God speaking to us in the Scriptures. Here, “the Father who is in heaven comes lovingly to meet his children, and talks with them. And such is the force and power of the Word of God that it can serve the Church as her support and vigor, and the children of the Church as strength for their faith, food for the soul, and a pure and lasting fount of spiritual life.” The Christian faithful are to be led to an ever deeper appreciation of the psalms as the voice of Christ and the voice of his Church at prayer (Sing to the Lord: Music in Divine Worship, USCCB, 2007).
The Entrance and Communion chants with their psalm verses serve to accompany the two most important processions of the Mass: the entrance procession, by which the Mass begins, and the Communion procession, by which the faithful approach the altar to receive Holy Communion (Sing to the Lord: Music in Divine Worship, USCCB, 2007).
Mgr. Wadsworth speaks about this in his article above:
*I think we are currently well placed to respond to this desire and this is evidenced by the fact that many things which were indicated fifty years ago, such as the singing of the Mass, and more particularly the singing of the proper texts rather than the endless substitution of songs and hymns, are only now being seriously considered and implemented. It is earnestly to be desired that such developments continue to flourish and that an improved liturgical culture is accessible to everyone in the Church. *