In this regard, priests have a "great responsibility ... to preside at the Eucharist in persona Christi and to provide a witness to and a service of communion not only for the community directly taking part in the celebration, but also for the universal Church, which is a part of every Eucharist."
Here, the Pope uses his strongest language in the encyclical: "It must be lamented that, especially in the years following the post-conciliar liturgical reform, as a result of a misguided sense of creativity and adaptation there have been a number of abuses which have been a source of suffering for many. A certain reaction against 'formalism' has led some, especially in certain regions, to consider the 'forms' chosen by the Church's great liturgical tradition and her Magisterium as non-binding and to introduce unauthorised innovations which are often completely inappropriate.
"I consider it my duty, therefore to appeal urgently that the liturgical norms for the celebration of the Eucharist be observed with great fidelity ... Liturgy is never anyone's private property, be it of the celebrant or of the community in which the mysteries are celebrated. The Apostle Paul had to address fiery words to the community of Corinth because of grave shortcomings in their celebration of the Eucharist resulting in divisions (schismata) and the emergence of factions (haireseis) (see 1 Cor 11:17-34).
He continues: "Our time, too, calls for a renewed awareness and appreciation of liturgical norms as a reflection of, and a witness to, the one universal Church made present in every celebration of the Eucharist. Priests who faithfully celebrate Mass according to the liturgical norms, and communities which conform to those norms, quietly but eloquently demonstrate their love for the Church.
"Precisely to bring out more clearly this deeper meaning of liturgical norms, I have asked the competent offices of the Roman Curia to prepare a more specific document, including prescriptions of a juridical nature, on this very important subject."
The Holy Father concludes his encyclical: "Every commitment to holiness, every activity aimed at carrying out the Church's mission, every work of pastoral planning, must draw the strength it needs from the Eucharistic mystery and in turn be directed to that mystery as its culmination.
"In the Eucharist we have Jesus, we have his redemptive sacrifice, we have his resurrection, we have the gift of the Holy Spirit, we have adoration, obedience and love of the Father ...
"The mystery of the Eucharist - sacrifice, presence, banquet - does not allow for reduction or exploitation; it must be experienced and lived in its integrity".