The entire letter may be found here but I wished to share a few excerpts which relate to some particular points we tend to emphasize here, including, incidentally, the matter of ad orientem. (That said, there are some other aspects of this same letter which are critiquable, so do read on until the end.)
The first excerpt I wished to share considers the liturgy taken in whole and in relation to the sacrament of the Eucharist (and in particular I would draw your attention to the three main outlines found toward the end):
The Eucharist is the Mystery of Mysteries as Pascha is the Feast of Feasts
7. The community of the faithful lives by faith in the mystery of Christ. The sacraments are facets, transfigurations or appearances of the mystery of God who took human form to make humanity in his divine form. Since the Eucharist is the sacrament of all sacraments, it crowns all the various prayers and liturgical services. The Eucharist is like Pascha: it is not in the line of feasts, but the pinnacle, as our liturgical prayers say. Pascha is the “feast of feasts and the celebration of celebrations.” (Eighth Ode of the Paschal Canon)
Indeed there is an essential link between Pascha and the Eucharist, for it is the sacramental place, in which Christ’s Passover is extended to become the Church’s, as the fourth-century Saint Gregory Nazianzus described it, “The offering of the resurrection,” and the fourteenth century Nicholas Cabasilas wrote, “The icon of the Saviour’s economy.” For the eucharistic spirituality of the Liturgy is condensed and the liturgical year’s spirituality meet in their three main outlines:
i. The service of the Word corresponds to Theophany (Christmas, the Baptism and the preaching of the Gospel)
ii. The service of the Anaphora corresponds to Pascha (the Passion, Crucifixion and Resurrection)
iii. The service of Communion corresponds to theosis
In another section, we turn to the familiar theme of the sacred liturgy as a foretaste of heaven:
The Liturgy as a Foretaste of the Kingdom
14. In the Divine Liturgy, we live in a special way, whilst still being on earth, the heavenly Liturgy, in which the myriads of angels, ascribe glory and praise to the Divine Trinity, one in essence, saying, “Holy, holy, holy, Lord God of Sabaoth. Heaven and earth are full of thy glory.” (cf. Isaiah 6: 3) It is the heavenly song that we hear being repeated in the heart of the church. We have added to that the earthly hymn, in which Jerusalem welcomes the King coming to save, “Blessed is he that cometh in the name of the Lord; Hosanna in the highest.” (Matthew 21: 9b)
15. The Divine Liturgy translates us to heaven, for it opens up to us an eschatological dimension and “we take part in a foretaste of that heavenly liturgy which is celebrated in the holy city of Jerusalem toward which we journey as pilgrims.”(Vatican II Constitution on the Sacred Liturgy, no. 8)
16. The Divine Liturgy brings heaven to us too and allows it to enter our everyday life. The Church or Eucharistic community is the place of new birth through the Holy Spirit, the birth that our Lord Jesus Christ gave us in the mystery of his death and resurrection. It is a community of the Gospel and Eucharist. It is the Body of Christ is the place of Pentecost, where the Holy Spirit comes down and changes the bread and wine into the Body and Blood of Christ, just as He changes the faithful to become other Christs, and transforms the whole of creation into the living temple of God, in which is repeated in its vaults, songs and hymns of thanksgiving and praise, for the whole of creation “groaneth ...waiting for the ...redemption...” (Romans 8: 22-23)
17. So the earth becomes heaven and life becomes in the Christian vision a universal, cosmic Divine Liturgy. That is why it is said that the Divine Liturgy is heaven on earth.
On ad orientem, or liturgical prayer toward the East:
41. The Instruction ["APPLYING THE LITURGICAL PRESCRIPTIONS OF THE CODE OF CANONS OF THE EASTERN CHURCHES", Congregation for Eastern Churches, 1996] mentions the importance of Praying towards the East in No. 107, “Ever since ancient times, it has been customary in the prayer of the Eastern Churches to prostrate oneself to the ground, turning toward the east; the buildings themselves were constructed such that the altar would face the east. Saint John of Damascus explains the meaning of this tradition: ‘It is not for simplicity nor by chance that we pray turned toward the regions of the east .... Since God is intelligible light (1 John 1: 5), and in the Scripture, Christ is called the Sun of justice (Malachi 3: 20) and the East (Zechariah 3: 8 of the LXX), it is necessary to dedicate the east to him in order to render him worship. The Scripture says: 'Then the Lord God planted a garden in Eden, in the east, and he placed there the man whom he had formed' (Genesis 2: 8). ... In search of the ancient homeland and tending toward it, we worship God. ...Waiting for him, we prostrate ourselves toward the east. It is an unwritten tradition, deriving from the Apostles.’
This rich and fascinating interpretation also explains the reason for which the celebrant who presides in the liturgical celebration prays facing the east, just as the people who participate. It is not a question, as is often claimed, of presiding the celebration with the back turned to the people, but rather of guiding the people in pilgrimage toward the Kingdom, invoked in prayer until the return of the Lord.
Such practice, threatened in numerous Eastern Catholic Churches by a new and recent Latin influence, is thus of profound value and should be safeguarded as truly coherent with the Eastern liturgical spirituality.”
On fidelity to tradition (while permitting development in continuity with the same):
43. The Instruction emphasises the importance of faithfulness to the tradition. We read in no. 109, “It cannot be denied that the Eastern Catholic Churches have been exposed, in rather recent times, to the influence of sacred art styles completely foreign to their heritage, concerning both the external form of sacred buildings and the arrangement of the interior space and sacred images. Yet, from the preceding observations emerges a harmonious unity of words, gestures, space, and objects proper and specific to each of the Eastern liturgies. Continuous reference must be made to this aspect when planning new places of worship. To do so naturally requires on the part of the clergy an in-depth knowledge of their own tradition and a constant, well established, and systematic formation of the faithful so that they may be able to fully perceive the richness of the signs entrusted to them. Fidelity does not imply anachronistic fixation, as the evolution of sacred art—even in the East—demonstrates, but rather, development that is fully coherent with the profound and immutable meaning of how it is celebrated in the liturgy.”
Finally, I cannot help but share the follow (rather blunt) comment, obviously directed at those complaining about the length of the Melkite Divine Liturgy:
70. We have had enough of hearing about a long or short Divine Liturgy, long or short service. We only hear this remark as far as the Liturgy or prayer service is concerned. We never hear about a long or short visit, session in front of the television or the computer, evening with friends or at a dance. We think that these remarks about the length of prayer services are futile and unworthy. Let us take our watches off when we go into the atmosphere of prayer. Let us lay aside our earthly watches and earthly timetables when we enter God’s house. “It is time for the Lord to act.” That is how the Divine Liturgy begins and it is completely for the Lord. It is to that that our liturgical prayers very often exhort us, saying, “Let us lay aside all earthly cares...” and “no-one who is bound by earthly cares and material concerns...” and further, “let our hearts be lifted up unto the Lord...let us attend,” and St. Basil the Great says, “Do not hurry through your prayer. Do not abridge it to make time for worldly business. Pay no regard to people’s faces, but rather direct your heart completely to the King enthroned before you with the angels attending him.”
Now all this said, I would be remiss to not make note of the fact that this document has received some mixed reviews, not for the reason of the quoted sections above (which are quite good), but rather because some of the specifics surrounding the "practical guidance" noted in the document. Guidance which, as one Eastern Christian noted to me, is understood as possibly mimicking some of the very things that Latin rite Catholics have found to not have worked out liturgically.
