What did Jeroboam immediately do after becoming ruler of the northern tribes?
He immediately set up idolatrous worship and led the northern ten tribes into idolatry. This made the northern kingdom the first part of Israel to fall into abject idolatry, beginning a downward decline, while Judah would follow roughly 150 years later.
Les explains that after the nation divided, the northern kingdom under Jeroboam was the first part of Israel to go into abject idolatry. He says Jeroboam immediately set up idolatrous worship and immediately led the northern ten tribes into idolatry. As a result, they would go down the banana peel first, and 150 years later Judah would follow. Later in the context Les points to 2 Kings 17 and the fall of these northern tribes about 740 or 750 B.C., reviewing how Israel went down and down over hundreds of years.