2 Chronicles 13:3
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. 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.
This verse belongs to the reign of Abijah in Judah, during the period after Solomon's death when the kingdom had divided, with Jeroboam among those ruling Israel. The account of Abijah's reign is given more fully in Chronicles.
The verse records Abijah of Judah and Jeroboam of Israel drawing up their armies for battle, with 400,000 chosen valiant warriors for Abijah and 800,000 chosen mighty men of valour for Jeroboam, twice as many. The confrontation stands in the context of Abijah's appeal to Israel not to fight against God, whose covenant with David guaranteed the kingdom to the house of David.
Judah was attacked from both front and rear, but Abijah called on the Lord and the Lord helped Judah. Judah conquered in the war, with Israel defeated in a decisive victory. The battle between Judah and Israel illustrates the American Civil War between North and South, with Jeroboam's revolt corresponding to Southern secession and his attack on Abijah to the Confederate effort to bring the North under its rule.