Vatican Website Translation:
7. To accomplish so great a work, Christ is always present in His Church, especially in her liturgical celebrations. He is present in the sacrifice of the Mass, not only in the person of His minister, “the same now offering, through the ministry of priests, who formerly offered himself on the cross” , but especially under the Eucharistic species. By His power He is present in the sacraments, so that when a man baptizes it is really Christ Himself who baptizes . He is present in His word, since it is He Himself who speaks when the holy scriptures are read in the Church. He is present, lastly, when the Church prays and sings, for He promised: “Where two or three are gathered together in my name, there am I in the midst of them” (Matt. 18:20) .
Christ indeed always associates the Church with Himself in this great work wherein God is perfectly glorified and men are sanctified. The Church is His beloved Bride who calls to her Lord, and through Him offers worship to the Eternal Father.
Rightly, then, the liturgy is considered as an exercise of the priestly office of Jesus Christ. In the liturgy the sanctification of the man is signified by signs perceptible to the senses, and is effected in a way which corresponds with each of these signs; in the liturgy the whole public worship is performed by the Mystical Body of Jesus Christ, that is, by the Head and His members.
From this it follows that every liturgical celebration, because it is an action of Christ the priest and of His Body which .s the Church, is a sacred action surpassing all others; no other action of the Church can equal its efficacy by the same title and to the same degree.
7. Ad tantum vero opus perficiendum, Christus Ecclesiae suae semper adest, praesertim in actionibus liturgicis. Praesens adest in Missae Sacrificio cum in ministri persona, “idem nunc offerens sacerdotum ministerio, qui seipsum tunc in cruce obtulit”(20), tum maxime sub speciebus eucharisticis. Praesens adest virtute sua in Sacramentis, ita ut cum aliquis baptizat, Christus ipse baptizet(21). Praesens adest in verbo suo, siquidem ipse loquitur dum sacrae Scripturae in Ecclesia leguntur. Praesens adest denique dum supplicat et psallit Ecclesia, ipse qui promisit: “Ubi sunt duo vel tres congregati in nomine meo, ibi sum in medio eorum” (Mt 18,20).
Reapse tanto in opere, quo Deus perfecte glorificatur et homines sanctificantur, Christus Ecclesiam, sponsam suam dilectissimam, sibi semper consociat, quae Dominum suum invocat et per ipsum Aeterno Patri cultum tribuit.
Merito igitur Liturgia habetur veluti Iesu Christi sacerdotalis muneris exercitatio, in qua per signa sensibilia significatur et modo singulis proprio efficitur sanctificatio hominis, et a mystico Iesu Christi Corpore, Capite nempe eiusque membris, integer cultus publicus exercetur.
Proinde omnis liturgica celebratio, utpote opus Christi sacerdotis eiusque Corporis, quod est Ecclesia, est actio sacra praecellenter, cuius efficacitatem eodem titulo eodemque gradu nulla alia actio Ecclesiae adaequat.
Slavishly Literal Translation:
7. In fact for completing so great a work, Christ is always present to his Church, especially in liturgical actions. He is present in the Sacrifice of the Mass, both in the person of the minister, “the same one now offering by the ministry of priests, who offered himself then on the cross” [Council of Trent, Session XXII, 17 September 1562, Doctrine Concerning the Most Holy Sacrifice of the Mass, c. 2], and especially under the Eucharistic species. He is present in his own power in the Sacraments, so that when someone baptizes, Christ himself baptizes [St. Augustine, Tractate on the Gospel of John VI, c. 1, n. 7]. He is present in his word, so that he himself speaks when the sacred Scriptures are read in the Church. Finally he is present when the Church makes supplication and sings [psalms], he himself who promised, “Where there are two or three gathered in my name, there am I in their midst.” [Matthew 18:20].
Actually, in so great a work, by which God is perfectly glorified and human beings are sanctified, Christ always associates the Church, his most well-beloved spouse, with himself, who invokes her Lord and through him offers worship to the Eternal Father.
Properly, therefore, the Liturgy is held as an exercise of the priestly munus [office, duty, gift] of Jesus Christ, in which human sanctification is signified by sensible signs and effected in a manner proper to each, and integral public worship is exercised by the mystical Body of Jesus Christ — to be sure, by the Head and his members.
Accordingly, all liturgical celebration, insofar as it is the work of Christ the priest and his Body, which is the Church, is sacred action of surpassing excellence, whose efficacy no other action of the Church is equal in title or rank.
Article 7 is the climax of SC’s treatment of the nature of the Liturgy. The text does not settle the disputed theological question of a strictly technical definition of the sacred Liturgy by proximate genus and specific difference. It pre-supposes the teaching of Mediator Dei ##20 and 22.
Article 7, paragraph 1 is notable for its articulation of the multiple modes of Christ’s presence disclosed in liturgical actions: person of the minister, Eucharistic species, sacramental action, proclamation of scripture, the Church’s prayer and song.
Article 7, paragraph 2, highlights and modifies Pius X’s teaching in Tra le sollecitudini that the Liturgy includes directly not only the worship which the Church offers to Christ and through him to the Father but also the sanctification which the Father bestows on worshipers through Christ. (Note that the text does not directly state that this worship/sanctification occurs “in the Holy Spirit.”)
Article 7, paragraph 3, adds but adds a new emphasis to the teaching in Mediator Dei: it belongs to the essence of the Liturgy to take place in signs perceivable by the senses.
Article 7, paragraph 4 seems to be an attempt to account for the scholastic distinction between efficacy understood ex opere operato and that understood ex opere operantis without using scholastic terminology. There is also a hint of what will appear in later Council documents of conceptualizing the offices of Christ as priestly, prophetic, and kingly, with consequences for our understanding of the Church’s mission and structure.