A prophetic condemnation of wealth is very surprising because in the Hebrew Bible, wealth is often a form of blessing, just pure wealth. For example, to Abraham, God promises, I will give you progeny; I will give you people; and I will give you land; the two most important assets in creating wealth.
But what happened in the eighth century is that the wealth was being generated unjustly; and so you have a merging—from the north, Amos and Hosea, from the south, Micah and Isaiah—that’s condemning this gain of wealth, not just wealth in itself, but the gain of wealth through unjust means.
For example, Amos, the most vociferous of all these prophets, he makes no reference to idolatry. Now what kind of prophet makes no reference to idolatry? But for Amos, this exploitive, economic, unjust gain was so distasteful that that was his focus of condemnation. It was: “why are generating this through exploiting the poor?” and that’s what makes it so surprising and interesting that the prophets arise with such a strong voice against the generation of wealth.