“Neither in conversation,” writes the theologian Billuart, “nor in discussion, nor in interpreting Scripture or the Fathers, nor in consulting, nor in giving his reasons for the point which he has defined, nor in answering letters, nor in private deliberations, supposing he is setting forth his own opinion, is the Pope infallible.”  He is not infallible as a theologian, or as a priest, or a Bishop, or a temporal ruler, or a judge, or a legislator, or in his political views, or even in the government of the Church:  but only when he teaches the Faithful throughout the world, ex cathedra, in matters of faith or of morals, that is to say, in matters relating to revealed truth, or to principles of moral conduct.

“It in no way depends upon the caprice of the Pope, or upon his good pleasure, to make such and such a doctrine the object of a dogmatic definition.  He is tied up and limited to the divine revelation, and to the truths which that revelation contains.  He is tied up and limited by the Creeds, already in existence, and by the preceding definitions of the Church.  He is tied up and limited by the divine law and by the constitution of the Church.  Lastly, he is tied up and limited by that doctrine, divinely revealed, which affirms that, alongside religious society, there is civil society, that alongside the Ecclesiastical Hierarchy, there is the power of temporal magistrates, invested, in their own domain, with a full sovereignty, and to whom we owe in conscience obedience and respect in all things morally permitted, and belonging to the domain of civil society."[8]

Further, a definition of divine faith must be drawn from the Apostolic deposit of doctrine, in order that it may be considered an exercise of infallibility, whether in Pope or Council.  Similarly, a precept of morals, if it is to be accepted as from an infallible voice, must be drawn from the moral law, that primary revelation to us from God.  The Pope has no power over the Moral Law, except to assert it, to interpret it and to enforce it.

6.  From this, it is at once realised how restricted, after all, is the infallible power of the Pope, in spite of the alarm its definition excited in the Protestant camp, in 1870.

Still, it must be clearly understood that whether speaking ex cathedra or not, the Pope is always the Vicar of Christ and the divinely appointed Head of His Church, and that we, as dutiful children, are bound both to listen to him with the utmost attention and respect, and to show him ready and heartfelt obedience.  Anyone who should limit his submission to the Pope’s infallible utterances is truly a rebel at heart, and no true Catholic.

The Holy Scripture is far from contemplating the exceptional cases of infallible definitions when it lays down the command:  “Remember them, who have the rule over you, who have spoken unto you the word of God, whose faith follow”.  And, “obey them that have the rule over you, and submit yourselves, for they watch for your souls, as they that must give account, that they may do it with joy, and not with grief”.  The margin in the Protestant Version (observes Cardinal Newman) reads “those who are your guides,” and the word may also be translated “leaders”.  Well, whether as rulers or as guides and leaders, whichever word be right, they are to be obeyed.