By Fr. William G. Most, EWTN - By the Magisterium we mean the teaching office of the Church… Christ promised to protect the teaching of the Church: "He who hears you, hears me; he who rejects you rejects me, he who rejects me, rejects Him who sent me"… Now of course the promise of Christ cannot fail: hence when the Church presents some doctrine as definitive or final, it comes under this protection, it cannot be in error; in other words, it is infallible…