And it came to pass, when he reigned, that he smote all the house of Jeroboam; he left not to Jeroboam any that breathed, until he had destroyed him, according unto the saying of the LORD, which he spake by his servant Ahijah the Shilonite:
When he became king, he attacked all of Jeroboam's family. He didn't let anyone from Jeroboam's family survive. This happened because the Lord said it would, as told through his prophet Ahijah from Shiloh.