2 Chronicles 13:1-3, 2-3

In the eighteenth year of the rule of King Jeroboam, Abijah took over the throne of Judah. He ruled in Jerusalem three years. His mother was Maacah daughter of Uriel of Gibeah.

War broke out between Abijah and Jeroboam. Abijah started out with 400,000 of his best soldiers; Jeroboam countered with 800,000 of his best.