This rule, which is of importance in order to understand any part of the New Testament, becomes of the highest necessity in any attempt to interpret the Revelation. The writer was evidently a diligent student of the older Scriptures, absorbing their images and emblems until they had become a part of himself. Much in his writings that at first seems obscure becomes plain when we put ourselves in his position and study the Scriptures, which were evidently in his thoughts. The prophetical books of the Old Testament especially are to be studied. Between the relation in which the older prophets stood to the laws and institutions of Moses and that which the apostles of the New Testament dispensation sustained to the Lord Jesus Christ a strong similarity exists. Neither the one nor the other claimed to be originators or independent discoverers, but rather witnesses to truths already revealed, which they accepted as primary and fundamental facts. Into the clear understanding, indeed, of these they were enabled by divine inspiration to look more deeply than others could, and they were also supernaturally aided to draw them out into great principles, capable of application to human thought and conduct in the shaping of individual and national life and practice. Thus, naturally and by sympathy of condition, the later writers found themselves led into careful and profound study of their predecessors. The prophecies of Daniel and Zechariah deserve to be especially consulted. Written, as they were, at or near the time of the captivity of Judah, they had peculiar interest for one who was himself an exile for the truth. Some of the imagery of the Revelation is drawn from the glowing poetry of Isaiah. And almost the entire Book of Joel has been worked into the Apocalypse. But of all helps to an understanding of the Revelation the most fruitful is a close and careful comparison with the Book of Ezekiel; especially is this the case in reference to the closing chapters of both. Between the authors of these two works there were striking similarities of character and condition. But a more powerful bond of union is found in the fact that both of them were preëminently prophets of the Holy Spirit, seeming to have reached truer and profounder views of his work in the economy of redemption than any predecessors in their separate dispensations. Isaiah and Paul wrote of Christ and his Church; but if we wish to learn the fullest development of the office of the Holy Ghost we must turn to the pages of Ezekiel and John.