To what degree the Book of the Twelve should be read as a unity is a question I have wrestled with for some time. On the one hand, I hear compelling arguments made by Paul House, James Nogalski, and Barry Jones, while on the hand, lingering questions disallow my full reception of this view. While re-reading a chapter in Forming Prophetic Literature: Essays on Isaiah and the Twelve in Honor of John D.W. Watts by Ehud ben Zvi, I found myself in the struggle for understanding once again.
One strand of evidence that is usual championed for the supposed unity of the Twelve is Sirach 49:10 which reads, “And may he cause the bones of the twelve prophets to flourish from their place, for they comforted Jacob and rescued them by assured hope” (translation mine). As I have thought about this text, the weight that has been hoisted upon as evidence for unity has diminished in my own mind in recent months. For, the mention of the twelve prophets together hardly necessitates a unified reading of their books as is so often intimated. Equally valid could be the understanding of the prophet’s ministries during a critical point in Israel’s history. Furthermore, the task that the prophets are commended for is that of comforting Israel. This effort need not demand their unity.
This, among other sources, that are typically used as evidence for unity have recently fallen somewhat on rocky soil in my own research. Though I remain open to compositional and canonical considerations, I can now see the danger of assuming the unity of the Twelve at the outset of one’s reading. I think ben Zvi says it well:
If a researcher adopts a strategy of interpretation based on a reading of the ‘Book of the Twelve’ as a coherent, unified, literary text, then it is likely that she or he will find or emphasize meanings and properties in the text that are different from those brought to the forefront by those who study each book as a separate unit.
Certainly this is a discussion that will continue for some time, and I hope to hear both side of the conversation. While writing this post I discovered another monograph that seeks to foster such a conversation (see here).
 Ehud ben Zvi, “Twelve Prophetic Books or ‘The Twelve’: A Few Preliminary Consideration” in Forming Prophetic Literature: Essays on Isaiah and the Twelve in Honor of John D.W. Watts (ed. James W. Watts and Paul R. House; JSOTSup 235; Sheffield: Sheffield Academic, 1996), 127-8.