[We should consider],—that great questions exist in the subject-matter of which Scripture treats, which Scripture does not solve; questions too so real, so practical, that they must be answered, and, unless we suppose a new revelation, answered by means of the revelation which we have, that is, by development. Such is the question of the Canon of Scripture and its inspiration: that is, whether Christianity depends upon a written document as Judaism;—if so, on what writings and how many;—whether that document is self-interpreting, or requires a comment, and whether any authoritative comment or commentator is provided;—whether the revelation and the document are commensurate, or the one outruns the other;—all these questions surely find no solution on the surface of Scripture, nor indeed under the surface in the case of most men, however long and diligent might be their study of it. Nor were these difficulties settled by authority, as far as we know, at the commencement of the religion; yet surely it is quite conceivable that an Apostle might have dissipated them all in a few words, had Divine Wisdom thought fit. But in matter of fact the decision has been left to time, to the slow process of thought, to the influence of mind upon mind, the issues of controversy, and the growth of opinion...81.
...Scripture expressly calls the Church "the pillar and ground of the Truth," and promises her as by covenant that "the Spirit of the Lord that is upon her, and His words which He has put in her mouth shall not depart out of her mouth, nor out of the mouth of her seed, nor out of the mouth of her seed's seed, from henceforth and for ever." (1 Tim. iii. 16; Isa. lix. 21) 106.
N.B. The page numbers which I provide (different from the Google book links I give) are references to my copy of An Essay on the Development of Christian Doctrine, John Henry Cardinal Newman, New York: Image, 1960.