The books of the four prophets advocate an unswerving faithfulness to God, and in the event of sin, they advocate repentance. A proper relationship with God was to manifest itself in three ways. First, the people would experience peace within their community (Isaiah 9:7); what the prophets saw instead was the ruthless pursuit of self-interest. Amos and Micah especially condemn those wealthy people who used their power and wealth to oppress the unfortunate. Isaiah and Jeremiah emphasize that the worship of only God, not the gods of the Assyrian and Babylonian conquerors, is necessary for living as God’s people. Although that idea may seem self-evident to modern Westerners, it was novel in ancient biblical times.
Second, living in faithfulness to God would result in justice in the land. Justice was first and foremost the responsibility of the king (Isaiah 9:7; 11:3-5). In Amos (5:21-24), God rejects worship and sacrifices that are not tied to justice for the poor. Micah (6:8) ties justice to kindness toward other human beings and humility before God. Judeans were to act in ways that guaranteed protection to the poor.
Third, living in faithfulness to God was the means to hope for the future. The prophets were sober in their assessment of the power of Assyria and Babylon vis-à-vis Judah. Its only hope was that God would aid Judah for remaining faithful.
These prophets made predictions. Sometimes they seemed to be without qualifications. Jeremiah, for example, became convinced that Babylon would capture Jerusalem and that the only prudent action, therefore, was for Judah to surrender to the conqueror. Other times, however, prophetic predictions seem to have been conditional. In his Temple sermon, Jeremiah (7:1-15; 26:1-6) warned that the Temple would be destroyed if the people of Judah did not repent. Still other predictions may have been fulfilled in the past (such as the restitution of the Levitical priesthood after the Exile) and others in ways the prophets did not anticipate (such as Isaiah 7:14). Still others perhaps have not been fulfilled (Isaiah 65:17-25), at least not yet.