Thoughtful men, with hearts craving the truth, have come to seek in the Catholic Church the road which leads with surety to eternal life. They have understood that they could not cleave to Jesus Christ as the Head of the Church if they did not belong to the Body of Jesus Christ which is the Church. Nor could they ever hope to possess in all its purity the faith of Jesus Christ if they were to reject its legitimate teaching authority entrusted to Peter and his successors.