It is necessary to obey a Pope in all things as long as he does not go against the universal customs of the Church, but should he go against the universal customs of the Church, he need not be followed.
Pope Innocent IIIThe mysteries of the faith are not to [be] explained rashly to anyone. Usually in fact, they cannot be understood by everyone but only by those who are qualified to understand them with informed intelligence. The depth of the divine Scriptures is such that not only the illiterate and uninitiated have difficulty understanding them, but also the educated and the gifted.
Pope Innocent IIIWe believe that the Greeks have been punished through [the Crusades] by the just judgement of God: these Greeks who have striven to rend the Seamless Robe of Jesus Christ ... Those who would not join Noah in his ark perished justly in the deluge; and these have justly suffered famine and hunger who would not receive as their shepherd the blessed Peter, Prince of the Apostles.
Pope Innocent IIINot to oppose erroneous doctrine is to approve of it, and not to defend at all true doctrine is to suppress it.
Pope Innocent IIIThis [Magna Carta] has been forced from the King. It constitutes an insult to the Holy See, a serious weakening of the royal power, a disgrace to the English nation, a danger to all Christendom, since this civil war obstructs the crusade. Therefore?we condemn the charter and forbid the King to keep it, or the barons and their supporters to make him do so, on pain of excommunication.
Pope Innocent III