יהושע, פרק י״א, פסוק ה׳

Facing the advancing Israelites, the various regional kings decide to join forces and prepare for battle. At a basic level, this coalition is a straightforward gathering and assembly of armies [מצודת ציון, ביאור שטיינזלץ]. However, the alliance is not a spontaneous reaction. It is a highly coordinated military move where the kings agree on a specific, predefined time and date to meet. They purposefully choose the area of the Waters of Merom as the location to camp together and launch their war [מלבי״ם].