12 tribes of Israel. 12 Minor Prophets. Obviously just a coincidence.
Well, not really. In the Hebrew Bible, the number twelve is the number one numerical symbol of God’s people—there were originally twelve tribes in the unified nation of Israel, and it’s possible that the twelve Minor Prophets collected in one scroll symbolize the prophesied restoration of the twelve tribes in a re-unified Israel and Judah. Bringing the twelve back together as one is such an important theme that it even pops up in the first chapter of the first Minor Prophet, Hosea, who predicts,
The people of Judah and the people of Israel shall be gathered together, and they shall appoint for themselves one head; and they shall take possession of the land, for great shall be the day of Jezreel. (NRSV Hosea 1:1)
In fact, some scholars believe that Micah was originally part of another book, but it was separated out to make a total of twelve books. The duct tape on Malachi in the original Minor Prophets scroll is something of a giveaway.