This is a document from the papacy of Blessed John Paul II (Vatican website)
The Church Is the Body of Christ
General Audience November 20, 1991
St. Paul uses the metaphor of the body to represent the Church. He says: “For in one Spirit we were all baptized into one body, whether Jews or Greeks, slaves or freemen, and we were all given to drink of one Spirit” (1 Cor 12:13). It is a new image. While the concept of the “People of God” which we explained in the preceding catecheses belongs to the Old Testament and is taken up again and enriched in the New Testament, the image of the body of Christ, which Vatican II also used in speaking about the Church, has no precedents in the Old Testament. It is found in the Pauline letters, which we shall especially refer to in this catechesis. This concept has been studied by exegetes and theologians of our century in its Pauline origin, in the patristic and theological tradition which derives from it, and in the validity which it also possesses for presenting the Church today. It was also employed by the papal Magisterium. Pope Pius XII devoted a memorable encyclical to it, with the title of Mystici Corporis Christi (1943).
We must also note that in the Pauline letters we do not find the adjective “mystical,” which only appears later; the letters speak of the body of Christ simply and with a realistic comparison to the human body. The Apostle writes: “As a body is one though it has many parts, and all the parts of the body, though many, are one body, so it is with Christ” (1 Cor 12:12).
With these words the Apostle intends to highlight both the unity and multiplicity which is proper to the Church. “For as in one body we have many parts, and all the parts do not have the same function, so we, though many, are one body in Christ and individually parts of one another” (Rom 12:4-5). It may be said that, although the concept of People of God highlights the multiplicity, that of body of Christ emphasizes the unity within this multiplicity, pointing out especially the principle and source of this unity: Christ. “You are Christ’s body, and individually parts of it” (1 Cor 12:27). “We, though many, are one body in Christ” (Rom 12:5). Therefore, this concept highlights the unity of Christ and the Church, and the unity of the Church’s many members among themselves, in virtue of the unity of the entire body with Christ.
The body is an organism which, precisely as an organism, expresses the need for cooperation among the individual organs and parts in the unity of the whole, which is put together and structured in such a way, according to St. Paul, “that there may be no division in the body, but that the parts may have the same concern for one another” (1 Cor 12:25). “Indeed, the parts of the body that seem to be weaker are all the more necessary” (1 Cor 12:22). We are, the Apostle adds, “individually parts of one another” (Rom 12:5) in the body of Christ, the Church. The multiplicity of the members and the variety of their functions cannot damage this unity, just as, on the other hand, this unity cannot cancel or destroy the multiplicity and variety of the members and their functions.
The need for “biological” harmony in the human organism is applied analogously in theological language to indicate the necessity of solidarity among all the members of the Church community. The Apostle writes: “If one part suffers, all the parts suffer with it; if one part is honored, all the parts share its joy” (1 Cor 12:26).
Thus, the concept of Church as the body of Christ can be said to complement the concept of People of God. The same reality is expressed according to the two aspects of unity and multiplicity by two different analogies.
The analogy of the body especially highlights the unity of life: the Church’s members are united with one another through the principle of unity in an identical life which comes from Christ. “Do you not know that your bodies are members of Christ?” (1 Cor 6:15). It is a spiritual life; in fact, it is life in the Holy Spirit. We read in Lumen Gentium: “By communicating his Spirit, Christ made his brothers, called together from all nations, mystically the components of his own body” (LG 7). In this way, Christ himself is “the head of the body, the Church” (Col 1:18). The condition for participating in the life of this body is the bond with the head, that is, with him “from whom the whole body, supported and held together by its ligaments and bonds, achieves the growth that comes from God” (Col 2:19).
The Pauline concept of the head (Christ, the head of the body which is the Church) signifies first of all the power which he possesses over the whole body. It is a supreme power, in regard to which we read in Ephesians that God “put all things beneath his feet and gave him as head over all things to the Church” (Eph 1:22). As head, Christ fills the Church, his body, with his divine life, so that all may grow “into him who is the head, Christ, from whom the whole body, joined and held together by every supporting ligament, with the proper functioning of each part, brings about the body’s growth and builds itself up in love” (Eph 4:15-16).
As head of the Church, Christ is the principle and source of cohesion among the members of his body (cf. Col 2:19). He is the principle and source of growth in the Spirit: from him the entire body grows and “builds itself up in love” (Eph 4:16). This is the reason for the Apostle’s exhortation to live “the truth in love” (Eph 4:15). The spiritual growth of the Church’s body and its individual members is a growth “from Christ” (the principle) and also “into Christ” (the goal). The Apostle tells us this when he finishes his exhortation with these words: “Living the truth in love, we should grow in every way into him who is the head, Christ” (Eph 4:15).
(to be continued, because of length)
