There is one body, the mystical body of Christ; and as the human body, in all its different organs and members, is one living unit by reason of the spirit of life that pervades it, so the Church, with its manifold diversities of organization and belief, is one, because animated by the one Holy Spirit.
Many earnest and holy men refuse outward fellowship with those who do not belong to their communion; but they are still one with them, since the Holy Spirit is in them all. And they will recognise this on the shore of Eternity.