King Amaziah of Judah was looking to go to war against Edom. Despite having an army of 300,000 soldiers, he hired 100,000 mercenaries from Israel.
A man of God—a man without a name—came to Amaziah to remind him that God was not with Israel and would not support its soldiers, even if they were fighting for Judah. He prophesies that an army from Judah with Israelite soldiers would be defeated regardless of the enemy.
Amaziah, amazingly, relents and sends back the mercenaries, even though he forfeits the hundred talents of silver he had paid for them.
Unfortunately, the mercenaries don’t take it so well. While Amaziah is out at war, they raid a number of towns in Judah and kill 3,000 people. The story doesn’t end here, but it involves another very minor prophet, so we’ll leave it for now.