דברי הימים א, פרק י״ט, פסוק י״ב

Facing a war on two parallel fronts requires a careful and unified strategy. When a military commander divides an army to address threats coming from different directions, the separation of troops is only part of the plan. Beyond simply splitting the forces, a clear pact of mutual assistance is established. Each division is assigned to act as a backup for the other.

If the battle becomes too difficult and one commander finds himself struggling against the enemy army, the agreement guarantees immediate support. The second commander will step in to reinforce him, effectively functioning as a reserve force to ensure neither side is overwhelmed [ביאור שטיינזלץ].