יואל, פרק ד׳, פסוק י״ב

A call goes out to the nations of the world, urging them to wake up and gather for a final, decisive battle. The nations are summoned to rouse themselves and prepare for the conflict that lies ahead [מצודת ציון, אבן עזרא]. Following this great awakening, all the nations will travel to the Valley of Jehoshaphat, which has been destined to serve as the ultimate battlefield [מצודת דוד].

The selection of this specific valley is not an accident. The very fact that the war unfolds in this exact location is meant to serve as a clear testament to the wickedness of these nations. It is within this valley that God will take His seat to pass judgment on all the surrounding peoples. There, He will hold them fully accountable and punish them for all the evil acts they have committed [מצודת דוד].