The human body formed by the Holy Ghost in the chaste womb of the Virgin Mother, and the mystical body which she brought forth by her travail on Calvary are both alike the body of the Incarnate Word. Indeed, one may say in a sense that the human body was assumed for the sake of the mystical body so that the mystical body could also be formed; just as, according to St Thomas, the first effect of the Sacrament of the holy Eucharist, of the real presence of the body and blood of Christ on the altar, is the unity of the mystical body. Therefore the members of the mystical body are likened to the members of Christ's physical body, his hands and feet, etc. and therefore they must serve his purposes, be used in his work in the same way, and, if completely united to him, to the same extent as were his other members.