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

The Mystical Body of Christ unites the faithful with Christ, their Head

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

After pondering all this long and seriously before God We consider it part of Our pastoral duty to explain to the entire flock of Christ through this Encyclical Letter the doctrine of the Mystical Body of Christ and of the union in this Body of the faithful with the divine Redeemer; and then, from this consoling doctrine, to draw certain lessons that will make a deeper study of this mystery bear yet richer fruits of perfection and holiness. Our purpose is to throw an added ray of glory on the supreme beauty of the Church; to bring out into fuller light the exalted supernatural nobility of the faithful who in the Body of Christ are united with their Head; and finally, to exclude definitely the many current errors with regard to this matter.

When one reflects on the origin of this doctrine, there come to mind at once the words of the Apostle: “Where sin abounded, grace did more abound.”6 All know that the father of the whole human race was constituted by God in so exalted a state that he was to hand on to his posterity, together with earthly existence, the heavenly life of divine grace. But after the unhappy fall of Adam, the whole human race, infected by the hereditary stain, lost their participation in the divine nature,7 and we were all “children of wrath.”8 But the all-merciful God “so loved the world as to give His only-begotten Son,”9 and the Word of the Eternal Father with the same divine love assumed human nature from the race of Adam – but as an innocent and spotless nature – so that He, as the new Adam, might be the source whence the grace of the Holy Spirit should flow unto all the children of the first parent. Through the sin of the first man they had been excluded from adoption as children of God; through the Word incarnate, made brothers according to the flesh of the only-begotten Son of God, they receive also the power to become the sons of God.10 As He hung upon the Cross, Christ Jesus not only appeased the justice of the Eternal Father which had been violated, but He also won for us, His brethren, an ineffable flow of graces. It was possible for Him of Himself to impart these graces to mankind directly; but He willed to do so only through a visible Church made up of men, so that through her all might cooperate with Him in dispensing the graces of Redemption. As the Word of God willed to make use of our nature, when in excruciating agony He would redeem mankind, so in the same way throughout the centuries He makes use of the Church that the work begun might endure.11

6 Rom., V, 20.
7 Cf. II Peter, I, 4.
8 Eph., II, 3.
9 John, III, 16.
10 Cf. John, I, 12.
11 Cf. [First] Vat. Council, Const. de Eccl., prol.

Mystici Corporis Christi 11-12

False rationalism and false mysticism both distort the Faith

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

For while there still survives a false rationalism, which ridicules anything that transcends and defies the power of human genius, and which is accompanied by a cognate error, the so-called popular naturalism, which sees and wills to see in the Church nothing but a juridical and social union, there is on the other hand a false mysticism creeping in, which, in its attempt to eliminate the immovable frontier that separates creatures from their Creator, falsifies the Sacred Scriptures.

As a result of these conflicting and mutually antagonistic schools of thought, some through vain fear, look upon so profound a doctrine as something dangerous, and so they shrink from it as from the beautiful but forbidden fruit of paradise. But this is not so. Mysteries revealed by God cannot be harmful to men, nor should they remain as treasures hidden in a field, useless. They have been given from on high precisely to help the spiritual progress of those who study them in a spirit of piety. For, as the [First] Vatican Council teaches, “reason illumined by faith, if it seeks earnestly, piously and wisely, does attain under God, to a certain and most helpful knowledge of mysteries, by considering their analogy with what it knows naturally, and their mutual relations, and their common relations with man’s last end,” although, as the same holy Synod observes, reason, even thus illumined, “is never capable of understanding those mysteries as it does those truths which forms its proper object.”5

5 Sessio III; Const. de fide cath., c. 4.

Mystici Corporis Christi 9-10

Increasing interest in the Faith and in liturgy brings cautious optimism

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

We have been no less consoled to know that with spontaneous generosity a fund has been created for the erection of a church in Rome to be dedicated to our saintly predecessor and patron, Eugene I. At this temple, to be built by the wish and through the liberality of all the faithful, will be a lasting memorial of this happy event, so We desire to offer this Encyclical Letter in testimony of Our gratitude. It tells of those living stones which rest upon the living cornerstone, which is Christ, and are built together into a holy temple, far surpassing any temple built by hands, into a habitation of God in the Spirit.4

But the chief reason for Our present exposition of this sublime doctrine is Our solicitude for the souls entrusted to Us. Much indeed has been written on this subject; and We know that many today are turning with greater zest to a study which delights and nourishes Christian piety. This, it would seem, is chiefly because a revived interest in the sacred liturgy, the more widely spread custom of frequent Communion, and the more fervent devotion to the Sacred Heart of Jesus practiced today, have brought many souls to a deeper consideration of the unsearchable riches of Christ which are preserved in the Church. Moreover, recent pronouncements on Catholic Action, by drawing closer the bonds of union between Christians and between them and the ecclesiastical hierarchy and especially the Roman Pontiff, have undoubtedly helped not a little to place this truth in its proper light. Nevertheless, while We can derive legitimate joy from these considerations, We must confess that grave errors with regard to this doctrine are being spread among those outside the true Church, and that among the faithful, also, inaccurate or thoroughly false ideas are being disseminated which turn minds aside from the straight path of truth.

4 Cf. Eph., II, 21-22; I Peter, II, 5.

Mystici Corporis Christi 7-8

The Mystical Body unites Catholics in charity under the protection of the Holy Father

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

Moreover, We trust that Our exposition of the doctrine of the Mystical Body of Christ will be acceptable and useful to those also who are without the fold of the Church, not only because their good will toward the Church seems to grow from day to day, but also because, while before their eyes nation rises up against nation, kingdom against kingdom, and discord is sown everywhere together with the seeds of envy and hatred, if they turn their gaze to the Church, if they contemplate her divinely-given unity—by which all men of every race are united to Christ in the bond of brotherhood—they will be forced to admire this fellowship in charity, and with the guidance and assistance of divine grace will long to share in the same union and charity.

There is a special reason too, and one most dear to Us, which recalls this doctrine to Our mind and with it a deep sense of joy. During the year that has passed since the twenty-fifth anniversary of Our Episcopal consecration, We have had the great consolation of witnessing something that has made the image of the Mystical Body of Jesus Christ stand out most clearly before the whole world. Though a long and deadly war has pitilessly broken the bond of brotherly union between nations, We have seen Our children in Christ, in whatever part of the world they happened to be, one in will and affection, lift up their hearts to the common Father, who, carrying in his own heart the cares and anxieties of all, is guiding the barque of the Catholic Church in the teeth of a raging tempest. This is a testimony to the wonderful union existing among Christians; but it also proves that, as Our paternal love embraces all peoples, whatever their nationality and race, so Catholics the world over, though their countries may have drawn the sword against each other, look to the Vicar of Jesus Christ as to the loving Father of them all, who, with absolute impartiality and incorruptible judgment, rising above the conflicting gales of human passions, takes upon himself with all his strength the defence of truth, justice and charity.

Mystici Corporis Christi 5-6