Christopher R. Seitz explains how:
Attention to the canonical shaping helps us see that even the individual prophets belong to a larger history and sweep than they as individual were able to recognize at the time (and this pains Habakkuk when he does recognize it, in the transition from one age of violence, the Assyrian, to the next, the Babylonian). And what is true of these prophets as men within Israel’s history – and this is a history with Israel and the nations and the created order itself, and is no private affair: this is what attention to the Twelve as a whole shows us – will become a fact in respect of a history including Israel and the nations and creation in Jesus Christ. Israel’s history as depicted in the Twelve is a type or figure of a larger history, and a story that takes two Testaments to tell. Amos is a man among the Twelve, and the Twelve are men related to one man – Jesus Christ.
I am trying to show that identification with the world of the prophet is available on terms other than usual experiential access, in romantic “behind-the-text” or postmoder “in-front-of-the-text” modes.
Prophecy and Hermeneutics: Toward a New Introduction of the Prophets, pg. 242. (Bold emphasis mine.)
As I’ve been wrestling with Joel lately, this quote is especially meaningful. While Joel has relevance to pre-exilic and exilic Judean prophetic tradents, this relevance is transformed beyond the prophet’s wildest imagination as it is picked up and re-employed as a testimony to none other than Jesus Christ.
Reading Hosea-Malachi as a single book (like Ezekiel or Jeremiah) reveals new levels of meaning at the corpus level which demand our attention and testify to the coming work of Christ in exciting and mysterious ways!