דברי הימים ב, פרק כ׳, פסוק ג׳

Facing a massive, united enemy army is a terrifying prospect for any leader. Following the sudden alliance of rival kingdoms and the arrival of their overwhelming military force, King Jehoshaphat was struck with deep fear over the looming danger [ביאור שטיינזלץ].

Rather than panicking or relying solely on military strategy, the king chose to respond to this terror with a profound spiritual shift. He placed his complete trust in God, turning entirely to Him to seek His help and guidance [מצודת דוד]. To bring the nation into this spiritual effort, Jehoshaphat called for a public fast. He organized a day of national gathering for all the people, dedicating the time entirely to unified prayer and sincere pleading before God [ביאור שטיינזלץ].