The Pope should not flatter himself about his power nor should he rashly glory in his honor and high estate, because the less he is judged by man, the more he is judged by God. Still the less can the Roman Pontiff glory because he can be judged by men, or rather, can be shown to be already judged, if for example he should wither away into heresy; because he who does not believe is already judged, In such a case it should be said of him: 'If salt should lose its savor, it is good for nothing but to be cast out and trampled under foot by men.'
Pope Innocent IIIEvery cleric must obey the Pope, even if he commands what is evil; for no one may judge the Pope.
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 III