Consistent with their canonical focus, the authors argue on p199-200 that there are dangers in relying upon context within the latter prophetic books (eg. Amos) themselves:
The main source for discovering the background of the ministry of Amos is what can be gleaned from the book itself, which raises the dangers inherent in mirror-reading. (p199)
In other words, our access to and knowledge of the Sitz in Leben of Amos and his historic ministry may be less secure than commonly thought, and there is the peril of circular reasoning, attempting a social reconstruction on the basis of Amos’s words and then proceeding to use that reconstructed setting of eighth-century Israel to interpret the words of the prophet. (p199-200)
I think that the authors have over-stated the problem, and that the canonical approach for which they are advocating, while helpful, is not as important as an “all of Scripture as context” approach which tends, of course, to universalize the passage. But I am comfortable with this approach, and feel that in recent decades (maybe even the last hundred years?) that the original historical context has been over-emphasized in much teaching and preaching.
The failure of the brief titles to specify to whom the prophet speaks (whether to Judah, Israel, or the exiles), which information is often in the superscription, is a feature that helps to universalize their message. (p201)