1 Kings 12:30

And this thing became a sin: for the people went to worship before the one, even unto Dan.

Cross-reference

1 Kings 13:34 repeats the phrase 'this thing became sin' and declares it led to Jeroboam's dynasty being cut off — the direct consequence.

1 Kings 14:16 states God will give up Israel because of Jeroboam's sins he caused Israel to commit — the same sin here is the reason for judgment.

2 Kings 17:21 Historical context

2 Kings 17:21 summarizes that Jeroboam caused Israel to commit great sin — the same sin that eventually led to the northern kingdom's exile.

2 Chronicles 17:4 says Jehoshaphat walked in God's commands 'not according to the practices of Israel' — contrasting his faithfulness with Jeroboam's sinful pattern.