Christ Himself has said: They are no longer two, but they are one flesh (Matt. 19:6). Is it strange then, if they are one flesh, that they should have one tongue and should say the same words, since they are one flesh, Head and body? Let us therefore hear them as one. But let us listen to the Head speaking as Head, and to the body speaking as the body. We do not separate the two realities, but two different dignities; for the Head saves, and the body is saved.

pp. 419-420 - On the Mystical Body of Christ