12:12-15
And why did Rehoboam choose the foolish advice, rather than the sensible advice of the elders? Maybe it was out of pride, or seeking to demonstrate his own authority. Whatever the case, he answered the people harshly. Note that while the subsequent events were the outcome of Rehoboam's stupidity, the text makes it clear that it was the Lord’s will that was being fulfilled. The sovereignty of God and human responsibility are not in conflict.
12:16-24
Rehoboam’s decision has the inevitable consequences, the people think they have no part in Rehoboam’s kingdom, nor David’s, so they abandon him and “went home”. 12:18,19 describes the sorry state of affairs. Only Judah remained loyal to David. Benjamin was also with David. There was war between \Israel and Judah. Fortunately the war was stopped by the Lord. The problem was not Israel, but disobedience.