Matthew Poole and continuators on 2 Chronicles 13:7

7 And there are gathered unto him vain men, the children of Belial , and have strengthened themselves against Rehoboam the son of Solomon, when Rehoboam was young and tender-hearted , and could not withstand them.

Such as have cast off the Yoke and Obedience which they owed both to God and to their King.

Not in Age, for he was then 41 years old, but in his Kingdom, which he had but newly obtained, and in Experience in Politick, and especially in Military, Affairs, to which he was wholly a Stranger, as having been born and bred up in a time of great Peace and Security.

i. e. Cowardly and fearful, who durst not adventure to chastise the Rebels as he should have done. But herein Abijah forgets his Duty both to his Father, whom he falsely traduceth; and to God, by whose Express Command Rehoboam was restrained from the War against Israel, which otherwise he had both Courage and Resolution to prosecute, as appears from the History, 1 King. 12. 21.