"When the shepherd turns into a wolf, it behooves the flock to defend itself in the first place. Doctrine normally flows from the bishops down to the faithful people, and subjects should not judge their chiefs. But, in the treasure of revelation, there are certain points that every Christian necessarily knows and must obligatorily defend." (L'anne liturgique - Le temps de la septuagesime, 1932)
"The pope can neither make nor unmake a sacrament; he cannot affect the essence of any sacrament in any way. He cannot touch the Bible; he can neither take away a text from the inspired Scriptures nor add one to them. He has no fresh inspiration nor revelation. "His business is to believe the revelation of Christ, as all Catholics believe it, and to defend it against heresy....
(The Early Papacy to the Synod of Chalcedon in 451, pp. 27-28)