The answer to the question of how to account for the tripartite division involves the most careful investigation of the whole process by which the canon actually took shape. If the entire canon of the Old Testament were formed, as some allege, by one man, or by one set of men, in a single age, then it is obvious that the books must have been separated into three groups on the basis of some material differences in their contents. If, on the other hand; the process of canonization was gradual and extended over several generations, then the various books were separated from one another probably because one section of the canon was closed before certain other books of similar character were written. At any rate it is difficult to see why Kings and Chronicles are not included in the same division, and especially strange that Daniel does not stand among the prophets. To explain this mystery, medieval Jews were wont to say that "the Prophets were inspired by the spirit of prophecy, whereas the Writings by the Holy Spirit," implying different degrees of inspiration. But this is a distinction without a difference, the Holy Spirit and the spirit of prophecy are one and the same. Modern Protestants distinguish between the donum propheticum and the munus propheticum, i.e. between the gift and the office of prophecy. They allow that Daniel possessed the gift of prophecy, but they deny that he was Divinely appointed to the office of prophet. But compare
Mt 24:15, which speaks of "Daniel the prophet," and on the other hand,
Am 7:14, in which Amos resents being considered a prophet. Oehler modifies this explanation, claiming that the threefold division of the canon corresponds to the three stages of development in the religion of Israel, namely, Mosaism, Prophetism, and Hebraism. According to Oehler, the Law was the foundation of the entire canon. From it there were two lines of development, one objective, the Prophets, the other subjective, the Writings. But Oehler's theory does not satisfactorily account for Ezra and Nehemiah and Chronicles, being in the third division; for in what sense can they be said to be more subjective than Judges, Samuel, and Kings? The Septuagint version (250-150 BC) takes no notice of the tripartite division. The true solution probably is that the process was gradual. When all the witnesses have been examined, we shall probably discover that the Law was canonized first, the Prophets considerably later, and the Writings last of all. And it may further become evident that the two last divisions were collected synchronously, and hence, that the tripartite divisions of the canon are due to material differences in their contents as well as to chronology.