"Every time," says Dr. Harnack, "the political situation culminated in a crisis for the people of God, the apocalypses appeared stirring up the believers; in spirit, form, plan, and execution they closely resembled each other.... They all spoke in riddles; that is, by means of images, symbols, mystic numbers, forms of animals, etc., they half concealed what they meant to reveal. The reasons for this procedure are not far to seek: (1.) Clearness and distinctness would have been too profane; only the mysterious appears divine. (2.) It was often dangerous to be too distinct." [Footnote: _Encyc. Brit._, xx. 496. ] That these writings appeared in troublous times, and that they dealt with affairs of the present and of the immediate future, must always be borne in mind. Certain symbolical conceptions are common to them; earthquakes denote revolutions; stars falling from heaven typify the downfall of kings and dynasties; a beast is often the emblem of a tyrant; the turning of the sun into darkness and the moon into blood signify carnage and destruction upon the earth. We have these symbolisms in several of the Old Testament writings as well as in many of the apocalyptical books which are not in our canon; and the interpretation of such passages is not at all difficult when we understand the usage of the writers. Of these apocalyptic books one of the most remarkable is the Book of Enoch, which appears to have been written a century or two before Christ. It purports to be a revelation made to and through the patriarch Enoch; it contains an account of the fall of the angels, and of a progeny of giants that sprung from the union of these exiled celestials with the daughters of men; it takes Enoch on a tour of observation through heaven and earth under the guidance of angels, who explain to him many things supernal and mundane; it deals in astronomical and meteorological mysteries of various sorts, and in a series of symbolical visions seeks to disclose the events of the future. It is a grotesque production; one does not find much spiritual nutriment in it, but Jude makes a quotation from it, in his epistle, as if he considered it Holy Scripture. "The Fourth Book of Esdras" is another Jewish book of the same kind, which may have been written about the hundredth year of our era. It purports to be the work of Ezra, whom it misplaces, chronologically, putting him in the thirtieth year of the Captivity. The problem of the writer is the restoration of the nation, destroyed and scattered by the Roman power. He makes the ancient scribe and law-giver of Israel his mouthpiece, but he is dealing with the events of his own time. Nevertheless, his allusions are veiled and obscure; he speaks in riddles, yet he speaks to a people who understand his riddles, and know how to take his symbolic visions. This book is in our English Apocrypha, under the title 2 Esdras.