2 Chronicles 13:7 Commentary - English Annotations on the Holy Bible by Matthew Poole
The children of Belial; such as have cast off the yoke and obedience which they owed both to God and to their king.
When Rehoboam was young; not in age, for he was then forty-one years old, but in his kingdom, which he had but newly obtained, and in experience in politic, 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.
Tender-hearted, i.e. cowardly and fearful, who durst not adventure to chastise the rebels as he should have done. But therein 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, 1Ki 12:21.
Consult other comments:
2 Chronicles 13:7 - Joseph Benson’s Commentary on the Old and New Testaments
2 Chronicles 13:7 - The Cambridge Bible for Schools and Colleges
2 Chronicles 13:7 - Adam Clarke's Commentary and Critical Notes on the Bible
2 Chronicles 13:7 - Companion Bible Notes, Appendices and Graphics
2 Chronicles 13:7 - Ellicott's Commentary for English Readers (Old and New Testaments)
2 Chronicles 13:7 - Geneva Bible Notes
2 Chronicles 13:7 - John Gill's Exposition of the Entire Bible
2 Chronicles 13:7 - English Annotations on the Holy Bible by Matthew Poole
2 Chronicles 13:7 - John Trapp's Complete Commentary (Old and New Testaments)
English Annotations on the Holy Bible by Matthew Poole

Matthew Poole (1624–1679) wrote English Annotations on the Holy Bible, completing the chapters as far as Isaiah 58 before his death in 1679. The rest of the Annotations were completed by friends and colleagues among his Nonconformist brethren. The first printing of the completed edition was in 1685, 2 volumes folio, followed by editions in 1688, 1696 (with valuable chapter outlines added by the editors, Samuel Clark and Edward Veale), and the 4th and definitive edition in 1700, the basis of all others.