The books of the classical prophets of the Old Testament contain two themes which are so interwoven that they strike the modern reader as indivisible parts of a single whole. Oracles denouncing the sin and apostasy of Israel and Judah alternate, in such books as Isaiah, Jeremiah, Amos, and Hosea, with predictions of national calamity-usually at the hands of foreign powers, though sometimes apparently by means of natural disasters. The predicted calamity is said by the prophets to be the direct result of the sins they denounce, and this leads in some places to a third theme, the urgent call to repent before it is too late.
