It is not because the Holy Scriptures do not contain, explicitly or implicitly, the whole faith, that, interpreted by private judgment, they give only a fallible rule of faith, but because, to find the faith in its unity and integrity in them, we must know it _aliunde_ and beforehand. This difficulty is completely obviated by the Catholic rule. The church has in Catholic tradition, which she preserves intact by time or change, the whole revelation, whether 156 written or unwritten, and in this tradition she has the key to the real sense of the sacred Scriptures, and is able to interpret them infallibly. Tradition, authenticated by the church as the witness and depositary of it, supplies the knowledge necessary to the understanding of the sacred text. Read in the light of tradition, what is implicit in the text becomes explicit, what is merely referred to as wholly known becomes expressly and clearly stated, and we are able to understand the written word, because tradition interprets it for us, without any demand for a knowledge or judgment on our part that exceeds our natural powers. Our judgment is no longer private judgment, because we have in tradition a catholic rule by which to judge, and our judgment has not to pass on anything above the province of reason. The objection we make to the Protestant rule, it must be obvious now to our friend, cannot be retorted. The Protestant must interpret the sacred Scriptures by his private judgment, which he cannot do without passing upon questions which transcend its reach. The Catholic exercises, of course, his judgment in accepting the infallible teachings of the church, but he is not required to pass upon any question above the reach of his understanding, or upon which, by his natural reason, he cannot judge infallibly, or with the certainty of actual and complete knowledge. He is not required to pass upon the truth of what the church teaches, for that follows from her divine institution and commission to teach the revelation God has made previously established. He has simply to pass upon the question, What is it she teaches, or presents clearly and distinctly to my understanding to be believed? and, in passing upon that question, my judgment has not to judge of anything beyond or above reason, and, therefore, is not fallible any more than in any other act of knowledge.