Its members being guided and directed by Christ the head and bound together by a supernatural life communicated to them by Christ through the sacraments
Mystical Body of the Church. The analogy borne by any society of men to an organism is sufficiently manifest. In every society the constituent individuals are united, as are also the members of a body, to effect a common end: while the parts they severally play correspond to the functions of the bodily organs. They form a moral unity. This, of course, is true of the Church, but the Church has also a unity of a higher order: it is not merely a moral but a mystical body. This truth, that the Church is the mystical body of Christ, all its members being guided and directed by Christ the head, is set forth by St. Paul in various passages, more especially in Ephesians, iv, 4-13 (cf. John, xv, 5-8). The doctrine may be summarized as follows: (I) The members of the Church are bound together by a supernatural life communicated to them by Christ through the sacraments (ibid., 5). Christ is the center and source of life to Whom all are united, and Who endows each one with gifts fitting him for his position in the body (ibid., 7-12). These graces, through which each is equipped for his work, form it into an organized whole, whose parts are knit together as though by a system of ligaments and joints (ibid., 16; Col., ii, 19). Through them, too, (2) the Church has its growth and increase, growing in extension as it spreads through the world, and intensively as the individual Christian develops in himself the likeness of Christ (ibid., 13-15). (3) In virtue of this union the Church is the fullness or complement (Greek: pleroma) of Christ (Eph., i, 23). It forms one whole with Him; and the Apostle even speaks of the Church as "Christ" (I Cor., xii, 12). (4) This union between head and members is conserved and nourished by the Holy Eucharist. Through this sacrament our incorporation into the Body of Christ is alike outwardly symbolized and inwardly actualized; "We being many are one bread, one body; for we all partake of the one bread" (I Cor., x, 17).
G. H. JOYCE