A fourth source of materials, which is but another vein of this scientific quarry, is the historical and literary investigation of the Bible.  This has not been so recently opened as is commonly supposed, but has been worked at intervals throughout the history of the Church, and notably at the Protestant Reformation.  Luther carefully reexamined the books of the Bible, and declared that it was a matter of indifference to him whether Moses was the author of the Pentateuch, pronounced the Books of the Chronicles less accurate historically than the Books of the Kings, considered the present form of the books of Isaiah, Jeremiah and Hosea probably due to later hands, and distinguished in the New Testament “chief books” from those of less moment.  Calvin, too, discussed the authorship of some of the books, and suggested Barnabas as the writer of the Epistle to the Hebrews.  But the Nineteenth Century witnessed a very thorough application to the Scriptures of the same methods of historical and literary criticism to which all ancient documents were subjected.  The result was the discovery of the composite character of many books, the rearrangement of the Biblical literature in the probable order of its writing, and the use of the documents as historical sources, not so much for the periods they profess to describe, as for those in and for which they were written.

We can assign the following elements in our contemporary Christian thought to these scholarly investigations: 

(1) The conception of revelation as progressive—­a mode of thought that falls in with the idea of development or evolution.

(2) The distinction between the Bible as literature, with the history, science, ethics and theology of its age, and the religious experience of which it is the record, and in which we find the Self-disclosure of God.

(3) An historical rather than a speculative Christ.  We do not begin (however we may end) with a Figure in the heavens, the eternal Son of God, but with Jesus of Nazareth.  This method of approaching Him reinforces the emphasis on His manhood which came from Humanitarianism.  Christianity, like the fabled giant, Antaeus, has always drawn fresh strength for its battles from touching its feet to the ground in the Jesus of historic fact.  It was so when Francis of Assisi recovered His figure in the Thirteenth Century, and when Luther rediscovered Him in the Sixteenth.  There can be little doubt but that fresh spiritual forces are to be liberated, indeed are already at work, from this new contact with the Jesus of history.

Still another opening in the scientific quarry is Psychology.  The last century saw great advances in the investigation of the mind of man, which revolutionized educational methods, gave new tools to novelists and historians, and threw new light on every aspect of the human spirit.  Psychologists turned their attention to religion, and have done much to chart out the movements of man’s nature in his response to his highest inspirations.  They have altered methods of Biblical education in our Sunday Schools, have shown us helpful and harmful ways of presenting religious appeals, and have given us scientific standards to test the value of the materials employed in public worship.