Summa de Ecclesia

Moreover the Church of holy God is recorded as being named the body of Christ. Whence the Apostle, speaking in Eph. 1, says: He gave him, namely God the Father, to be head over all the Church, which is his body. Here it must be observed that, just as blessed Hiero. says of the flesh of Christ in his work on the epistle to the Ephesians, as cited in ch. Dupliciter, on Consecration, dist. 2, that it is understood in two ways, so the body of Christ is taken in two ways. For the body of Christ means the body which he took from the Virgin, joined of carnal members in a natural structure. It also means the mystic body which is the Church, which body is connected and compacted of faithful persons of either sex in a spiritual structure. For the fuller understanding of this statement it is opportune to consider something concerning the signification of the term mystic. For mystic, as the Catholicon says, is derived from mystery. For in Greek mysticon is called secret in Latin, whence mystic is the same as sacred, divine, hidden, and figurative. And as far as a reason can be drawn from each of these significations of this word mystic when we say of the Church that she is the mystic body: first, because she is sacred or holy, according to the first interpretation, according to the word sung in the creed, The holy catholic Church, and in 1 Cor. 3, The temple of God is holy, which you are. Second, because she is divine, according to the second signification, for she has been made a partaker of the divine nature, according to the word said of her members in Ps. 81, I said, you are gods, and all sons of the Most High, and in 2 Pet. 1, Partakers of the divine nature. Third, because she is hidden, according to the third signification, for it is hidden from us, set in this pilgrimage, who simply and truly in act pertains to the unity of this body, as blessed Bern. says: Who can say, I am of the elect, I am of those predestined to life, I am of the number of the sons, since Scripture cries out against it: Man does not know whether he is worthy of hatred or love. More commonly, however, the Church is denominated the mystic body from the fourth signification, namely because it is figurative, whether said through figure or through similitude, as gathered from the Apostle, who often speaks of the Church after the similitude of the natural body of man. Here it must be noted that the reason of this mystic signification is gathered chiefly from four things among others. The first is the multitude of official members concurring in the composition of the body, for just as the natural human body is compacted of many members conformable in nature and deputed to various acts, so the body of the Church, constituted of many faithful deputed to various offices, is joined together. Whence the Apostle in 1 Cor. 10: We being many are one bread and one body. Upon which Augu. says: Typically, that is figuratively, the Church is called one bread and one body, because just as one bread is composed of many grains and one body of many members, so the Church is bound together of many faithful with charity joining them. And in Rom. 12 it is said: For as in one body we have many members, but all the members have not the same act, so we being many are one body in Christ, and individually members one of another, having gifts differing according to the grace given to us, etc. The second thing from which the similitude is intimated is the conformity and unity of the members with the head. Plainly, just as in the natural body of man the head is connatural to the rest of the body and is joined to it through the neck, from which, as from the more perfect part, namely that in which all the senses reside, sense and motion are diffused in fullness into the whole body, so in the body of the Church the head which is Christ, according to the word in Eph. 1, He gave him to be head over all the Church, which is his body, is connatural through the assumed nature to the rest of the body. And through faith, understood by the neck, Cant. 4: Your neck is as the tower of David, by which we are united to him. In Eph. 4: Christ the head, from whom the whole body, namely the Church, compacted and connected through every joint of subministration, the Gloss: that is, through faith and charity which join and make the members of Christ minister to one another. The third thing from which the reason of the mystic speech is taken is the unity of the spirit, for just as the natural body of man has one spirit vivifying the whole body and ruling all the members, so in the whole body of the Church there is one vivifying and ruling spirit, which is the Holy Spirit, of whom in 1 Cor. 12: And in one spirit we were all baptized into one body. The sense of this is, according to the Gloss, that we were baptized, that is washed, and led by one spirit into one body. Whence the Gloss says: Just as the whole body of man is quickened by one soul, so one spirit does all things in the members of Christ. And therefore in Eph. 4 it is said: One body and one spirit. The fourth thing in which the mystic similitude is observed is that, just as in the human body the head and members are said to constitute one person, so that it is called one man, as Augu. says on John, Homily 21, so after a fashion in the body of the Church. Whence the same Augu. on Ps. 61: For one man with his head and his body, Jesus Christ the savior of the body, and the members of the body, two in one flesh and in one voice and in one passion, and when iniquity shall have passed away, in one rest; thus far Augustine.

¹