Granting the truth of the title, that Amos had his prophetic eyes opened two years before the earthquake, it will be a sign of historical progress if we find in the book itself any allusions to the earthquake. Now these are present. In the first division we find none, unless the threat of God's visitation in the form of a shaking of the land be considered as a tremor communicated to the prophet's mind from the recent upheaval. But in the second division there is an obvious reference: the last of the unavailing chastisements, with which Jehovah has chastised His people, is described as a _great overturning_.[125] And in the third division, in two passages, the judgment, which Amos has already stated will fall in the form of an invasion, is also figured in the terms of an earthquake. Nor does this exhaust the tremors which that awful convulsion had started; but throughout the second and third divisions there is a constant sense of instability, of the liftableness and breakableness of the very ground of life. Of course, as we shall see, this was due to the prophet's knowledge of the moral explosiveness of society in Israel; but he could hardly have described the results of that in the terms he has used, unless himself and his hearers had recently felt the ground quake under them, and seen whole cities topple over. If, then, Amos began to prophesy two years before the earthquake, the bulk of his book was spoken, or at least written down, after the earthquake had left all Israel trembling.[126]