Now the divine mind is so far above us that we can reach it only if God Himself brings it down to us. He has to descend, to lift the veil from His immensity, not by opening to us, before the time, those sacred precincts which "eye hath never seen," but by emitting a ray of light to clear up our darkness, to give us a glimpse of the awful splendor which vibrates in those celestial realms where light and sound and warmth of eternal charity mingle in the sweet harmony of the divine Beauty whose tones speak now to our senses in separate forms. God descends to our humility to interpret His own image. First He came in human form, and told us all the things we were to believe and do. Then He sent the Paraclete, and under His direction men of God taught the same things. Then they wrote them, or, as St. John tells us, some of them. The Paraclete veils Himself, as our Lord had announced to His Apostles, in the Church, whose divinely constituted earthly chief was to be Peter--to the end of time. The Church, therefore, founded by Christ, and an ever-living emanation of the incessant activity of the Holy Spirit, although necessarily speaking to men through men, is the first and surest interpreter of the purpose and meaning of each and every part of Holy Writ.
And because God cannot contradict Himself it follows that every truth of the written word must correspond with every truth of the spoken word. In doubtful cases, therefore, as to the meaning of a word or text in the Sacred Writings, we have recourse to the supreme, divinely-guided judgment of the Church. Her doctrines, defined, are the first and most important criterion of Scriptural truth.
But the Church has not defined every expression of truth, though she holds the key to all truth. She points to the light which illumines our night; she declares the stars whence that light issues directly or by reflection; but she does not always indicate where the rays of the one body begin to mingle with those of the other, or what precise elements determine the motion or stability of each. Only when there are conflicts or threatened disturbances of the centres of attraction and repulsion she reaches out her anointed hand, informed with the magic power of her Creator and founder, and directs the courses of bodies that otherwise would clash unto mutual destruction. Hence the freedom of investigation allowed the Catholic student of the Scriptures is limited only by the rules of faith taught by the same divine Teacher who watches over the spoken and written revelation alike. And as, in cases where we have not the express command of a superior, we interpret his will by his known desires and views in other respects, so in the interpretation of those parts of Holy Writ regarding the meaning of which we have no definite expression in the doctrinal code of the Church, we follow the _analogy of faith_; which is manifest from the general consent of the Christian Fathers and Doctors, and from the teaching of learned and holy commentators. These we may safely follow in all doubtful cases, that is to say, where there is no evidence to show that they were mistaken, either through want of certain sources of information or proofs which we have at our command presently, or because they accepted the views of their time and people, feeling that any departure from the received tradition would make disturbance, and fail of its intended good effect.