It’s so very sad, only a generation after David (a man after God’s own heart), and then Solomon (his wise but misguided son), the kingdom is split for good. Both halves of Israel worship other gods, adopting the Canaanite practices that were so detestable in God’s sight.
Consequences follow, including what would have been a low point: the invasion of Judah by Egypt:
2 Chronicles 12:4, 9 Shishak conquered Judah’s fortified towns and then advanced to attack Jerusalem. … So King Shishak of Egypt came up and attacked Jerusalem. He ransacked the treasuries of the Lord’s Temple and the royal palace; he stole everything, including all the gold shields Solomon had made.
When God sent a prophet to tell them why it was all going so wrong (“You have abandoned me, so I am abandoning you to Shishak”), Rehoboam and Judah’s leaders humbled themselves and said, ‘The Lord is right in doing this to us!’
God softened his judgement in response, although He didn’t let them off the hook completely:
2 Chronicles 12:7-8 Since the people have humbled themselves, I will not completely destroy them and will soon give them some relief. I will not use Shishak to pour out my anger on Jerusalem. But they will become his subjects, so they will know the difference between serving me and serving earthly rulers.
That Bible blog 