דברי הימים א, פרק י״ט, פסוק ט׳

A carefully planned military ambush set the stage for a complex battle, as the Israelite army walked into a coordinated trap. The Ammonite army and their allies strategically divided their troops into two distinct formations. Their goal was to corner the Israelites, forcing them to fight on two fronts simultaneously.

The first force, composed of the Ammonites, took up positions directly facing their city gates [מצודת דוד]. This was a calculated tactical choice. By avoiding open combat, they could lean on the physical protection of the city's fortifications [ביאור שטיינזלץ].

The second force consisted of hired auxiliary armies [ביאור שטיינזלץ] led by kings from the regions of Ish-tob and Maacah [רלב״ג]. These troops were stationed completely separately in the open field. The primary approach among commentators is that this deployment established a distinct second front in the open terrain. The purpose of this deception was to position the hired armies directly behind the Israelites. While the Ammonites confronted the Israelites head-on at the city entrance, the allied kings were perfectly placed to attack the Israelite camp from the rear.