The reconciliation initiated by Our Lord’s Passion was reinforced at Pentecost

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

If we consider closely all these mysteries of the Cross, those words of the Apostle are no longer obscure, in which he teaches the Ephesians that Christ, by His blood, made the Jews and Gentiles one “breaking down the middle wall of partition . . . in his flesh” by which the two peoples were divided; and that He made the Old Law void “that He might make the two in Himself into one new man,” that is, the Church, and might reconcile both to God in one Body by the Cross.”40

The Church which He founded by His Blood, He strengthened on the Day of Pentecost by a special power, given from heaven. For, having solemnly installed in his exalted office him whom He had already nominated as His Vicar, He had ascended into Heaven; and sitting now at the right hand of the Father He wished to make known and proclaim His Spouse through the visible coming of the Holy Spirit with the sound of a mighty wind and tongues of fire.41 For just as He Himself when He began to preach was made known by His Eternal Father through the Holy Spirit descending and remaining on Him in the form of a dove,42 so likewise, as the Apostles were about to enter upon their ministry of preaching, Christ our Lord sent the Holy Spirit down from Heaven, to touch them with tongues of fire and to point out, as by the finger of God, the supernatural mission and office of the Church.

40 Cf. Eph., II, 14-16.
41 Cf. Acts, II, 1-4.
42 Cf. Luke, III, 22; Mark, I, 10.

Mystici Corporis Christi 32-33

The death of the Savior released the gifts of the Holy Ghost to the Church

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

But if our Savior, by His death, became, in the full and complete sense of the word, the Head of the Church, it was likewise through His blood that the Church was enriched with the fullest communication of the Holy Spirit, through which, from the time when the Son of Man was lifted up and glorified on the Cross by His sufferings, she is divinely illumined. For then, as Augustine notes,39 with the rending of the veil of the temple it happened that the dew of the Paraclete’s gifts, which heretofore had descended only on the fleece, that is on the people of Israel, fell copiously and abundantly (while the fleece remained dry and deserted) on the whole earth, that is on the Catholic Church, which is confined by no boundaries of race or territory. Just as at the first moment of the Incarnation the Son of the Eternal Father adorned with the fullness of the Holy Spirit the human nature which was substantially united to Him, that it might be a fitting instrument of the Divinity in the sanguinary work of the Redemption, so at the hour of His precious death He willed that His Church should be enriched with the abundant gifts of the Paraclete in order that in dispensing the divine fruits of the Redemption she might be, for the Incarnate Word, a powerful instrument that would never fail. For both the juridical mission of the Church, and the power to teach, govern and administer the Sacraments, derive their supernatural efficacy and force for the building up of the Body of Christ from the fact that Jesus Christ, hanging on the Cross, opened up to His Church the fountain of those divine gifts, which prevent her from ever teaching false doctrine and enable her to rule them for the salvation of their souls through divinely enlightened pastors and to bestow on them an abundance of heavenly graces.

39 Cf. De pecc. orig., XXV, 29: Migne, Patrologiæ Cursus completus, Series Latina, XLIV, 400.

Mystici Corporis Christi 31

By the power of the Cross, Our Lord unites and reigns over His Mystical Body

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

On the Cross then the Old Law died, soon to be buried and to be a bearer of death,36 in order to give way to the New Testament of which Christ had chosen the Apostles as qualified ministers;37 and although He had been constituted the Head of the whole human family in the womb of the Blessed Virgin, it is by the power of the Cross that our Savior exercises fully the office itself of Head of His Church. “For it was through His triumph on the Cross,” according to the teaching of the Angelic and Common Doctor, “that He won power and dominion over the gentiles”;38 by that same victory He increased the immense treasure of graces, which, as He reigns in glory in heaven, He lavishes continually on His mortal members; it was by His blood shed on the Cross that God’s anger was averted and that all the heavenly gifts, especially the spiritual graces of the New and Eternal Testament, could then flow from the fountains of our Savior for the salvation of men, of the faithful above all; it was on the tree of the Cross, finally, that He entered into possession of His Church, that is, of all the members of His Mystical Body; for they would not have been untied to this Mystical Body through the waters of Baptism except by the salutary virtue of the Cross, by which they had been already brought under the complete sway of Christ.

36 Jerome and Augustine, Epist. CXII, 14 and CXVI, 16: Migne, Patrologiæ Cursus completus, Series Latina, XXII, 924 and 943; St. Thos., Summa Theologiæ [ST] I-II, q. 103, a. 3, ad 2; a. 4; ad 1; Council of Flor. pro Jacob.: Mansi, Sacrorum Conciliorum Nova et Amplissima Collectio XXXI, 1738.
37 Cf. II Cor., III, 6.
38 Cf. ST III, q. 42, a. 1.

Mystici Corporis Christi 30

The Church was born in Our Lord’s Passion and Death

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

That [Christ] completed His work on the gibbet of the Cross is the unanimous teaching of the holy Fathers who assert that the Church was born from the side of our Savior on the Cross like a new Eve, mother of all the living.28 “And it is now,” says the great St. Ambrose, speaking of the pierced side of Christ, “that it is built, it is now that it is formed, it is now that it is . . . molded, it is now that it is created. . . . Now it is that arises a spiritual house, a holy priesthood.”29 One who reverently examines this venerable teaching will easily discover the reasons on which it is based.

And first of all, by the death of our Redeemer, the New Testament took the place of the Old Law which had been abolished; then the Law of Christ together with its mysteries, enactments, institutions, and sacred rites was ratified for the whole world in the blood of Jesus Christ. For, while our Divine Savior was preaching in a restricted area—He was not sent but to the sheep that were lost of the House of Israel30—the Law and the Gospel were together in force;31 but on the gibbet of His death Jesus made void the Law with its decrees32 fastened the handwriting of the Old Testament to the Cross,33 establishing the New Testament in His blood shed for the whole human race.34 “To such an extent, then,” says St. Leo the Great, speaking of the Cross of our Lord, “was there effected a transfer from the Law to the Gospel, from the Synagogue to the Church, from the many sacrifices to one Victim, that, as Our Lord expired, that mystical veil which shut off the innermost part of the temple and its sacred secret was rent violently from top to bottom.”35

28 Cf. Gen., III, 20.
29 Ambrose, In Luc, II, 87: Migne, Patrologiæ Cursus completus, Series Latina [P.L.], XV, 1585.
30 Cf. Matth., XV, 24.
31 Cf. St. Thos., I-II, q. 103, a. 3, ad 2.
32 Cf. Eph., II, 15.
33 Cf. Col., II, 14.
34 Cf. Matth., XXVI, 28; I Cor., XI, 25.
35 Leo the Great, Serm., LXVIII, 3: Migne, P.L. LIV, 374.

Mystici Corporis Christi 28-29

Christ is the builder and Savior of His Mystical Body

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

In the course of the present study, Venerable Brethren, we have thus far seen that the Church is so constituted that it may be likened to a body. We must now explain clearly and precisely why it is to be called not merely a body, but the Body of Jesus Christ. This follows from the fact that our Lord is the Founder, the Head, the Support and the Savior of this Mystical Body.

As We set out briefly to expound in what sense Christ founded His social Body, the following thought of Our predecessor of happy memory, Leo XIII, occurs to Us at once: “The Church which, already conceived, came forth from the side of the second Adam in His sleep on the Cross, first showed Herself before the eyes of men on the great day of Pentecost.”23 For the Divine Redeemer began the building of the mystical temple of the Church when by His preaching He made known His Precepts; He completed it when he hung glorified on the Cross; and He manifested and proclaimed it when He sent the Holy Ghost as Paraclete in visible form on His disciples.

For while fulfilling His office as preacher He chose Apostles, sending them as He had been sent by the Father24—namely, as teachers, rulers, instruments of holiness in the assembly of the believers; He appointed their Chief and His Vicar on earth;25 He made known to them all things and whatsoever He had heard from His Father;26 He also determined that through Baptism27 those who should believe would be incorporated in the Body of the Church; and finally, when He came to the close of His life, He instituted at the Last Supper the wonderful Sacrifice and Sacrament of the Eucharist.

23 Encycl. Divinum Illud: Acta Sanctæ Sedis, XXIX, p. 649.
24 John, XVII, 18.
25 Cf. Matth., XVI, 18-19.
26 John, XV, 15; XVII, 8 and 14.
27 Cf. John, III, 5.

Mystici Corporis Christi 25-27

Sin does not preclude reconciliation with the Mystical Body

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

Nor must one imagine that the Body of the Church, just because it bears the name of Christ, is made up during the days of its earthly pilgrimage only of members conspicuous for their holiness, or that it consists only of those whom God has predestined to eternal happiness. It is owing to the Savior’s infinite mercy that place is allowed in His Mystical Body here below for those whom, of old, He did not exclude from the banquet.20 For not every sin, however grave it may be, is such as of its own nature to sever a man from the Body of the Church, as does schism or heresy or apostasy. Men may lose charity and divine grace through sin, thus becoming incapable of supernatural merit, and yet not be deprived of all life if they hold fast to faith and Christian hope, and if, illumined from above, they are spurred on by the interior promptings of the Holy Spirit to salutary fear and are moved to prayer and penance for their sins.

Let every one then abhor sin, which defiles the mystical members of our Redeemer; but if anyone unhappily falls and his obstinacy has not made him unworthy of communion with the faithful, let him be received with great love, and let eager charity see in him a weak member of Jesus Christ. For, as the Bishop of Hippo remarks, it is better “to be cured within the Church’s community than to be cut off from its body as incurable members.”21 “As long as a member still forms part of the body there is no reason to despair of its cure; once it has been cut off, it can be neither cured nor healed.”22

20 Cf. Matth., IX, 11; Mark, II, 16; Luke, XV, 2.
21 August., Epist., CLVII, 3, 22: Migne, Patrologiæ Cursus completus, Series Latina [PL], XXXIII, 686.
22 August., Serm., CXXXVII, 1: PL XXXVIII, 754.

Mystici Corporis Christi 23-24

Matrimony and Holy Orders increase and strengthen Christian society

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

For the social needs of the Church Christ has provided in a particular way by the institution of two other Sacraments. Through Matrimony, in which the contracting parties are ministers of grace to each other, provision is made for the external and duly regulated increase of Christian society, and, what is of greater importance, for the correct religious education of the children, without which this Mystical Body would be in grave danger. Through Holy Orders men are set aside and consecrated to God, to offer the Sacrifice of the Eucharistic Victim, to nourish the flock of the faithful with the Bread of Angels and the food of doctrine, to guide them in the way of God’s commandments and counsels and to strengthen them with all other supernatural helps.

In this connection it must be borne in mind that, as God at the beginning of time endowed man’s body with most ample power to subject all creatures to himself, and to increase and multiply and fill the earth, so at the beginning of the Christian era, He supplied the Church with the means necessary to overcome the countless dangers and to fill not only the whole world but the realms of heaven as well.

Actually only those are to be included as members of the Church who have been baptized and profess the true faith, and who have not been so unfortunate as to separate themselves from the unity of the Body, or been excluded by legitimate authority for grave faults committed. “For in one spirit” says the Apostle, “were we all baptized into one Body, whether Jews or Gentiles, whether bond or free.”17 As therefore in the true Christian community there is only one Body, one Spirit, one Lord, and one Baptism, so there can be only one faith.18 And therefore, if a man refuse to hear the Church, let him be considered—so the Lord commands—as a heathen and a publican.19 It follows that those who are divided in faith or government cannot be living in the unity of such a Body, nor can they be living the life of its one Divine Spirit.

17Cor., XII, 13.
18 Cf. Eph., IV, 5.
19 Cf. Matth., XVIII, 17.

Mystici Corporis Christi 20-22

The members of the Mystical Body are nourished by the Sacraments

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

Now we see that the human body is given the proper means to provide for its own life, health and growth, and for that of all its members. Similarly, the Savior of mankind out of His infinite goodness has provided in a wonderful way for His Mystical Body, endowing it with the Sacraments, so that, as though by an uninterrupted series of graces, its members should be sustained from birth to death, and that generous provision might be made for the social needs of the Church. Through the waters of Baptism those who are born into this world dead in sin are not only born again and made members of the Church, but being stamped with a spiritual seal they become able and fit to receive the other Sacraments. By the chrism of Confirmation, the faithful are given added strength to protect and defend the Church, their Mother, and the faith she has given them. In the Sacrament of Penance a saving medicine is offered for the members of the Church who have fallen into sin, not only to provide for their own health, but to remove from other members of the Mystical Body all danger of contagion, or rather to afford them an incentive to virtue, and the example of a virtuous act.

Nor is that all; for in the Holy Eucharist the faithful are nourished and strengthened at the same banquet and by a divine, ineffable bond are united with each other and with the Divine Head of the whole Body. Finally, like a devoted mother, the Church is at the bedside of those who are sick unto death; and if it be not always God’s will that by the holy anointing she restore health to the mortal body, nevertheless she administers spiritual medicine to the wounded soul and sends new citizens to heaven—to be her new advocates—who will enjoy forever the happiness of God.

Mystici Corporis Christi 18-19

The life of the Church is dependent on all its members

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

But a body calls also for a multiplicity of members, which are linked together in such a way as to help one another. And as in the body when one member suffers, all the other members share its pain, and the healthy members come to the assistance of the ailing, so in the Church the individual members do not live for themselves alone, but also help their fellows, and all work in mutual collaboration for the common comfort and for the more perfect building up of the whole Body.

Again, as in nature a body is not formed by any haphazard grouping of members but must be constituted of organs, that is of members, that have not the same function and are arranged in due order; so for this reason above all the Church is called a body, that it is constituted by the coalescence of structurally untied parts, and that it has a variety of members reciprocally dependent. It is thus the Apostle describes the Church when he writes: “As in one body we have many members, but all the members have not the same office: so we being many are one body in Christ, and everyone members one of another.”16

One must not think, however, that this ordered or “organic” structure of the body of the Church contains only hierarchical elements and with them is complete; or, as an opposite opinion holds, that it is composed only of those who enjoy charismatic gifts – though members gifted with miraculous powers will never be lacking in the Church. That those who exercise sacred power in this Body are its chief members must be maintained uncompromisingly. It is through them, by commission of the Divine Redeemer Himself, that Christ’s apostolate as Teacher, King and Priest is to endure. At the same time, when the Fathers of the Church sing the praises of this Mystical Body of Christ, with its ministries, its variety of ranks, its officers, it conditions, its orders, its duties, they are thinking not only of those who have received Holy Orders, but of all those too, who, following the evangelical counsels, pass their lives either actively among men, or hidden in the silence of the cloister, or who aim at combining the active and contemplative life according to their Institute; as also of those who, though living in the world, consecrate themselves wholeheartedly to spiritual or corporal works of mercy, and of those in the state of holy matrimony. Indeed, let this be clearly understood, especially in our days, fathers and mothers of families, those who are godparents through Baptism, and in particular those members of the laity who collaborate with the ecclesiastical hierarchy in spreading the Kingdom of the Divine Redeemer occupy an honorable, if often a lowly, place in the Christian community, and even they under the impulse of God and with His help, can reach the heights of supreme holiness, which, Jesus Christ has promised, will never be wanting to the Church.

16 Rom., XII, 4.

Mystici Corporis Christi 15-17

Scripture and the Magisterium attest that the Church is a visible body

From Pope Pius XII’s encyclical Mystici Corporis Christi (1943):

If we would define and describe this true Church of Jesus Christ—which is the One, Holy, Catholic, Apostolic and Roman Church12—we shall find nothing more noble, more sublime, or more divine than the expression “the Mystical Body of Christ”—an expression which springs from and is, as it were, the fair flowering of the repeated teaching of the Sacred Scriptures and the Holy Fathers.

That the Church is a body is frequently asserted in the Sacred Scriptures. “Christ,” says the Apostle, “is the Head of the Body of the Church.”13 If the Church is a body, it must be an unbroken unity, according to those words of Paul: “Though many we are one body in Christ.”14 But it is not enough that the Body of the Church should be an unbroken unity; it must also be something definite and perceptible to the senses as Our predecessor of happy memory, Leo XIII, in his Encyclical Satis Cognitum asserts: “the Church is visible because she is a body.”15 Hence they err in a matter of divine truth, who imagine the Church to be invisible, intangible, a something merely “pneumatological” as they say, by which many Christian communities, though they differ from each other in their profession of faith, are untied by an invisible bond.

12 Cf. [First] Vat. Council, Const. de fide cath., c. 1.
13 Col., I, 18.
14 Rom., XII, 5.
15 Cf. Acta Sanctæ Sedis, XXVIII, p. 710.

Mystici Corporis Christi 13-14