Let us take first the simplest of these tasks—to ascertain the general period of the book. Twice—by the title and by the portion of narrative[115]—we are pointed to the reign of Jeroboam II., circa 783-743; other historical allusions suit the same years. The principalities of Palestine are all standing, except Gath;[116] but the great northern cloud which carries their doom has risen and is ready to burst. Now Assyria, we have seen, had become fatal to Palestine as early as 854. Infrequent invasions of Syria had followed, in one of which, in 803, Rimmon Nirari III. had subjected Tyre and Sidon, besieged Damascus, and received tribute from Israel. So far then as the Assyrian data are concerned, the Book of Amos might have been written early in the reign of Jeroboam. Even then was the storm lowering as he describes it. Even then had the lightning broken over Damascus. There are other symptoms, however, which demand a later date. They seem to imply, not only Uzziah's overthrow of Gath,[117] and Jeroboam's conquest of Moab[118] and of Aram,[119] but that establishment of Israel's political influence from Lebanon to the Dead Sea, which must have taken Jeroboam several years to accomplish. With this agree other features of the prophecy—the sense of political security in Israel, the large increase of wealth, the ample and luxurious buildings, the gorgeous ritual, the easy ability to recover from physical calamities, the consequent carelessness and pride of the upper classes. All these things imply that the last Syrian invasions of Israel in the beginning of the century were at least a generation behind the men into whose careless faces the prophet hurled his words of doom. During this interval Assyria had again advanced—in 775, in 773 and in 772.[120] None of these expeditions, however, had come south of Damascus, and this, their invariable arrest at some distance from the proper territory of Israel, may have further flattered the people's sense of security, though probably the truth was that Jeroboam, like some of his predecessors, bought his peace by tribute to the emperor. In 765, when the Assyrians for the second time invaded Hadrach, in the neighbourhood of Damascus, their records mention a pestilence, which, both because their armies were then in Syria, and because the plague generally spreads over the whole of Western Asia, may well have been the pestilence mentioned by Amos. In 763 a total eclipse of the sun took place, and is perhaps implied by the ninth verse of his eighth chapter. If this double allusion to pestilence and eclipse be correct, it brings the book down to the middle of the century and the latter half of Jeroboam's long reign. In 755 the Assyrians came back to Hadrach; in 754 to Arpad: with these exceptions Syria was untroubled by them till after 745. It was probably these quiet years in which Amos found Israel at ease in Zion.[121] If we went down further, within the more forward policy of Tiglath-Pileser, who ascended the throne in 745 and besieged Arpad from 743 to 740, we should find an occasion for the urgency with which Amos warns Israel that the invasion of her land and the overthrow of the dynasty of Jeroboam will be immediate.[122] But Amos might have spoken as urgently even before Tiglath-Pileser's accession; and the probability that Hosea, who prophesied within Jeroboam's reign, quotes from Amos seems to imply that the prophecies of the latter had been current for some time.

Towards the middle of the eighth century—is, therefore, the most definite date to which we are able to assign the Book of Amos. At so great a distance the difference of a few unmarked years is invisible. It is enough that we know the moral dates—the state of national feeling, the personages alive, the great events which are behind the prophet, and the still greater which are imminent. We can see that Amos wrote in the political pride of the latter years of Jeroboam's reign, after the pestilence and eclipse of the sixties, and before the advance of Tiglath-Pileser in the last forties, of the eighth century.

A particular year is indeed offered by the title of the book, which, if not by Amos himself, must be from only a few years later:[123] Words of Amos, which he saw in the days of Uzziah and of Jeroboam, two years before the earthquake. This was the great earthquake of which other prophets speak as having happened in the days of Uzziah.[124] But we do not know where to place the year of the earthquake, and are as far as ever from a definite date.

The mention of the earthquake, however, introduces us to the answer of another of our questions—whether, with all its unity, the Book of Amos reveals any lines of progress, either of event or of idea, either historical or logical.

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]

This proof of progress in the book is confirmed by another feature. In the abstract given above it is easy to see that the judgments of the Lord upon Israel were of a twofold character. Some were physical—famine, drought, blight, locusts, earthquake; and some were political—battle, defeat, invasion, captivity. Now it is significant—and I do not think the point has been previously remarked—that not only are the physical represented as happening first, but that at one time the prophet seems to have understood that no others would be needed, that indeed God did not reveal to him the imminence of political disaster till He had exhausted the discipline of physical calamities. For this we have double evidence. In chapter iv. Amos reports that the Lord has sought to rouse Israel out of the moral lethargy into which their religious services have soothed them, by withholding bread and water; by blighting their orchards; by a pestilence, a thoroughly Egyptian one; and by an earthquake. But these having failed to produce repentance, God must visit the people once more: how, the prophet does not say, leaving the imminent terror unnamed, but we know that the Assyrian overthrow is meant. Now precisely parallel to this is the course of the Visions in chapter vii. The Lord caused Amos to see (whether in fancy or in fact we need not now stop to consider) the plague of locusts. It was so bad as to threaten Israel with destruction. But Amos interceded, and God answered, It shall not be. Similarly with a plague of drought. But then the Vision shifts from the realm of nature to that of politics. The Lord sets the plumbline to the fabric of Israel's life: this is found hopelessly bent and unstable. It must be pulled down, and the pulling down shall be political: the family of Jeroboam is to be slain, the people are to go into captivity. The next Vision, therefore, is of the End—the Final Judgment of war and defeat, which is followed only by Silence.

Thus, by a double proof, we see not only that the Divine method in that age was to act first by physical chastisement, and only then by an inevitable, ultimate doom of war and captivity; but that the experience of Amos himself, his own intercourse with the Lord, passed through these two stages. The significance of this for the picture of the prophet's life we shall see in our next chapter. Here we are concerned to ask whether it gives us any clue as to the extant arrangement of his prophecies, or any justification for re-arranging them, as the prophecies of Isaiah have to be re-arranged, according to the various stages of historical development at which they were uttered.

We have just seen that the progress from the physical chastisements to the political doom is reflected in both the last two sections of the book. But the same gradual, cumulative method is attributed to the Divine Providence by the First Section: for three transgressions, yea, for four, I will not turn it back; and then follow the same disasters of war and captivity as are threatened in Sections II. and III. But each section does not only thus end similarly; each also begins with the record of an immediate impression made on the prophet by Jehovah (chaps. i. 2; iii. 3-8; vii. 1-9).