“For we keep the charge of the LORD our God, but you have forsaken him” (v11). King Abijah of Judah was confident that God would give them victory against the northern tribes that had rebelled. Those tribes had abandoned the pure worship of the God of Abraham and had instead created a different priest and sacrifice system, worshiping “what are no gods” (9). These false gods were useless in battle, and so Judah prevailed against northern Israel, because “they relied on the Lord” (v18).
“Behold, God is with us …” (v12). Seeking power, security, or comfort apart from God will only lead us to destruction. He is the only one with real power to rescue us from the enemy.