2 Chronicles 13:13 - Joseph Benson’s Commentary on the Old and New Testaments

But Jeroboam caused an ambushment to come behind While Abijah was discoursing, he took the advantage thus afforded him of sending a party of soldiers privately to lie in ambush, and attack Abijah's army behind, while he continued to face them with his main body. It does not appear that he made any answer to Abijah's speech. The longest sword, he thinks, must determine the matter, not the better cause.