"Surely then, if the revelations and lessons in Scripture are addressed to us personally and practically, the presence among us of a formal judge and standing expositor of its words is imperative. It is antecedently unreasonable to suppose that a book so complex, so unsystematic, in parts so obscure, the outcome of so many minds, times, and places, should be given us from above without the safeguard of some authority; as if it could possibly from the nature of the case, interpret itself. Its inspiration does but guarantee its truth, not its interpretation. How are private readers satisfactorily to distinguish what is didactic and what is historical, what is fact and what is vision, what is allegorical and what is literal, what is [idiomatic] and what is grammatical, what is enunciated formally and what occurs, what is only of temporary and what is of lasting obligations. Such is our natural anticipation, and it is only too exactly justified in the events of the last three centuries, in the many countries where private judgment on the text of Scripture has prevailed. The gift of inspiration requires as its complement the gift of infallibility."
-John Henry Cardinal Newman