Apologeticae sive Theologiae Fundamentalis, Tomus II (Pars Altera): Demonstratio Catholica

The Church is called neither the physical body of Christ nor the moral, but the mystical. It is not called the physical body of Christ; for the physical body of Christ, formed in the womb of the Virgin Mary, having suffered on the cross and risen from the sepulcher, consists of flesh and bones, like the bodies of other men. Yet neither is the Church called the merely moral body of Christ, because Christ is the head of the Church not only in that sense in which the presidents of other societies are the head of a moral body. Rather, Christ in a manner full of mysteries exercises upon the Church the same organic-supernatural power which a natural human head exercises upon the human organism. Hence the Church is the mystical body of Christ, whose head is Christ, and whose members are the faithful. The thesis is established:

1. From Sacred Scripture. Passing over those words by which both Christ and the apostles, speaking of the Church, almost always implicitly declare our thesis, we note the explicit doctrine of St. Paul, enunciated thus:

1 Cor 6, 13. 15. 17: "The body ... for the Lord, and the Lord for the body ... Know you not that your bodies are the members of Christ? ... But he who is joined to the Lord is one spirit." Author's rendering: Our body to Christ the head, but Christ the head to our body. Therefore not only our soul, but also our bodies are inserted into Christ as members. But if we adhere to Christ the head as His own members, we are also of one spirit, or life, with Christ.

1 Cor 12, 12-14. 20. 27: "For as the body is one and has many members, and all the members of the body, whereas they are many, yet are one body: so also is Christ [namely, the mystical Christ]. For in one Spirit we were all baptized into one body, whether Jews or Gentiles, whether slaves or free: and we have all been made to drink of one Spirit. For the body also is not one member, but many ... Many members indeed, but one body ... But you are the body of Christ, and members of member." Author's rendering: As the human body, so also Christ, i. e. the mystical Christ, or the Church. Many members constitute one human body, because they are informed by the same spirit. So also the individual faithful are individual members of Christ, but taken together they constitute one body of Christ, because they are imbued with the same Holy Spirit.¹

Eph 4, 11-13, 15-16: "And He Himself [Christ] gave some indeed apostles, some prophets, others evangelists, others pastors and teachers ... unto the building up of the body of Christ: until we all meet into a perfect man, into the measure of the age of the fullness of Christ ... Let us grow in Him in all things, who is the head, Christ: from whom the whole body, compacted and joined together through every joint of supply, according to the working in the measure of each single member, makes increase of the body unto the building up of itself in charity." That is: Christ instituted various offices and functions, that the Church, which is the body of Christ, might be built up and become more and more like the perfect man, Christ. Let us therefore grow according to the exemplar of the head and by the power of union with Christ the head, who joins and gathers together the whole body, and who, through, as it were, joints or channels, supplies ("through every joint of supply") power suited to the individual members ("according to the working in the measure of each single member"), in such a way that the whole body of the Lord is increased in charity.

Col 1, 18. 24: "And He is the head of the body, the Church, who is the beginning, the firstborn from the dead: that in all things He may hold the primacy ... Who now rejoice in my sufferings for you, and fill up those things that are wanting of the sufferings of Christ, in my flesh, for His body, which is the Church."

2. From the holy fathers innumerable testimonies could be adduced, from which we select these few (others to be added in the corollaries): St. Ignatius: "Through the cross Christ in His passion invites you, who are His members. The head, therefore, cannot be born separately without the members, God promising union, who Himself is union."² St. Irenaeus calls the Church "the great and glorious body of Christ"³ St. Gregory of Nazianzus: "For we are all one body in Christ, but individually members of Christ and of one another. For some rule and preside: others obey and are governed. And although the action of both is not the same, since to command and to be ruled by command are not the same thing, nevertheless both are made one in the one Christ, built and compacted by the same Spirit."⁴ St. Augustine: "The whole Christ is head and body. The head is the savior of the body, who has already ascended into heaven; the body, however, is the Church, which labors on earth. But unless this body adhered to its head by the bond of charity, so that one might be made from head and body, He would not, rebuking a certain persecutor from heaven, say: 'Saule, Saule, why do you persecute me' (Act 9, 4) ... What, my members? The head cried out on behalf of the members, and the members transfigured the head in themselves,"⁵ St. Gregory the Great: "For the whole holy universal Church is one body, constituted under Christ Jesus, namely, its head."⁶ St. John Chrysostom: "He unites us through many examples. But observe: He is the head, we are the body; between head and body there can be no interval; He is the foundation, we the building; He the vine, we the branches; He the bridegroom, we the bride; He the shepherd, we the sheep; He the way, we those who walk; again we the temple, He the inhabitant; He the firstborn, we the brothers; He the heir, we the coheirs; He the life, we the living; He the resurrection, we the rising; He the light, we the enlightened. All these things manifest unity, and do not allow anything empty to lie between, not even the least."⁷