Chapter 11 — Part I — Article IX (Of the Church)
Section 258. Q. Why is the Church one? A. Because she is one spiritual Body, has one Head, Christ, and is animated by one Spirit of God. There is one body and one Spirit, even as ye are called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all. Eph. iv. 4-6.