2 Chronicles 11:1
And when Rehoboam was come to Jerusalem, he gathered of the house of Judah and Benjamin an hundred and fourscore thousand chosen men, which were warriors, to fight against Israel, that he might bring the kingdom again to Rehoboam. And when Rehoboam was come to Jerusalem, he gathered of the house of Judah and Benjamin an hundred and fourscore thousand chosen men, which were warriors, to fight against Israel, that he might bring the kingdom again to Rehoboam.
After the northern tribes withdrew their allegiance, Rehoboam came to Jerusalem and gathered 180,000 chosen warriors from Judah and Benjamin. His intent was to fight against Israel, the northern tribes, so that he might bring the kingdom again under himself. God forbade this civil war because the division of the kingdom was His doing. The people obeyed God's prohibition, did not fight, and returned home.