What does 2 Chronicles 20:17 mean?

But you won’t have to fight this battle. Just take your positions, stand still, and watch how God saves you. Don’t be afraid or lose heart. Go out to face them tomorrow, because I’ll be with you.' 2 Chronicles 20:17 - Modern Text Bible

(God promises they won’t need to fight—just to trust him and show up, and he’ll handle the rest.)