The prophet then is made sure of his message by the agreement between the inward convictions of his soul and the outward events of the day. When these walk together, it proves that they have come of a common purpose. He who causes the events--it is Jehovah Himself, _for shall there be evil in a city and Jehovah not have done it?_--must be author also of the inner voice or conviction which agrees with them. _Who_ then _can but prophesy?_ Observe again that no support is here derived from miracle; nor is any claim made for the prophet on the ground of his ability to foretell the event. It is the agreement of the idea with the fact, their evident common origin in the purpose of Jehovah, which makes a man sure that he has in him the Word of God. Both are necessary, and together are enough. Are we then to leave the origin of the Word in this coincidence of fact and thought--as it were an electric flash produced by the contact of conviction with event? Hardly: there are questions behind this coincidence. For instance, as to how the two react on each other--the event provoking the conviction, the conviction interpreting the event? The argument of Amos seems to imply that the ethical principles are experienced by the prophet prior to the events which justify them Is this so, or was the shock of the events required to awaken the principles? And if the principles were prior, whence did Amos derive them? These are some questions that will lead us to the very origins of revelation. The greatest of the events with which Amos and his contemporaries dealt was the Assyrian invasion. In a previous chapter we have tried to estimate the intellectual effects of Assyria on prophecy.[157] Assyria widened the horizon of Israel, put the world to Hebrew eyes into a new perspective, vastly increased the possibilities of history and set to religion a novel order of problems. We can trace the effects upon Israel's conceptions of God, of man and even of nature.[158] Now it might be plausibly argued that the new prophecy in Israel was first stirred and quickened by all this mental shock and strain, and that even the loftier ethics of the prophets were thus due to the advance of Assyria. For, as the most vigilant watchmen of their day, the prophets observed the rise of that empire, and felt its fatality for Israel. Turning then to inquire the Divine reasons for such a destruction, they found these in Israel's sinfulness, to the full extent of which their hearts were at last awakened. According to such a theory the prophets were politicians first and moralists afterwards: alarmists to begin with, and preachers of repentance only second. Or--to recur to the language employed above--the prophets' experience of the historical event preceded their conviction of the moral principle which agreed with it.