The contents of the prophetic writings, notwithstanding their variety, easily fall into a few great masses. The chief are these three--Criticism, Denunciation and Comfort.
1. There is a great mass of what may be called Criticism. Standing on their watch-tower and turning their observation on the internal condition of the state, the prophets could nearly always discern diseased symptoms in the body corporate, and it was their duty to point them out. So Isaiah commences his prophecies: "The whole head is sick, and the whole heart faint. From the sole of the foot even unto the head there is no soundness in it; but wounds, and bruises, and putrifying sores: they have not been closed, neither bound up, neither mollified with ointment." And he thus gives expression to the obligation which was laid on him to make these discoveries known: "Cry aloud, spare not, lift up thy voice like a trumpet, and show My people their transgression, and the house of Jacob their sins."
The sins which the prophets had to reprehend were pretty uniform all through the prophetic period; and it is interesting to compare them with those by which our own age is afflicted. There is no school in which the conscience can be so well educated to a sense of public sin as in the writings of the prophets.
The root evil was always Idolatry. The nation was continually falling away from the worship of the true God to idols, or at least the worship of other deities was incorporated with that of Jehovah. This was always both a symptom of advanced degradation and the head and fountain of other evils of the worst kind. All the prophets attack it with all the weapons in their armoury--with hot indignation and close argument and scalding tears. Isaiah is remarkable for attacking it with raillery and sarcasm. He takes his readers into the idol workshop and details the process of their manufacture. He shows us the workmen, surrounded with their plates of metal and logs of wood, out of which the god is to be fashioned, and busy with their files and planes, their axes and hammers, putting together the helpless thing. The idolmaker, he says, has a fine ash or oak or cedar-tree, and makes a pretty idol with it; but with the same wood he lights his fire and cooks his dinner--"He burneth part thereof in the fire; with part thereof he eateth flesh; he roasteth roast and is satisfied; yea, he warmeth himself and saith, Aha, aha, I am warm, I have seen the fire; and the residue thereof he maketh a god, even his graven image; he falleth down unto it and worshippeth it and prayeth unto it, and saith, Deliver me, for thou art my god."