Abijah set the battle in array Namely, against Jeroboam, having, no doubt, God's authority to engage with him in battle. It is probable, indeed, that Jeroboam was the aggressor, and that what Abijah did was in his own necessary defence.
Related Commentaries of 2 Chronicles 13:3
2 Chronicles 13:3
3 And Abijah set the battle in array with an army of valiant men of war, even four hundred thousand chosen men: Jeroboam also set the battle in array against him with eight hundred thousand chosen men, being mighty men of valour.