Charles Spurgeon Commentary 2 Chronicles 12:1

"And it came to pass, when the kingdom of Rehoboam was established, and he was strong, that he forsook the law of Jehovah, and all Israel with him." — 2 Chronicles 12:1 (ASV)

And it came to pass, when Rehoboam had established the kingdom, and had strengthened himself, he forsook the law of the LORD, and all Israel with him.

They prospered, at first, by adhering to Jehovah. The good people from the neighboring land of Israel emigrated to them, strengthening them, but as soon as they grew strong, they forsook the law of Jehovah.

And it came to pass, when Rehoboam had established the kingdom, and had strengthened himself, he forsook the law of the LORD, and all Israel with him.

He was not able to endure the perils of prosperity. He forgot the Lord who had caused him to prosper; and, in the pride of his heart, he turned aside to idols.