דברי הימים א, פרק ד׳, פסוק מ״ב

A military expedition of five hundred warriors sets out toward Mount Seir, the historical territory of the Edomites. Their mission is to strike down the surviving remnants of Amalek, who had remained in the region since the wars fought during the reign of King Saul [ביאור שטיינזלץ]. The fighting force itself is drawn entirely from the tribe of Simeon, guided by four brothers who serve as their leaders and military captains [מצודת דוד].

However, the identity of these four brothers reveals an interesting dynamic. Although the army is made up of Simeonites, the commanders are the sons of Ishi, a family head from the tribe of Manasseh [רד״ק, מלבי״ם]. This unusual appointment of leaders from a different tribe is rooted in a historical tradition. Amalek is part of the lineage of Esau, and tradition dictates that the descendants of Esau can only be defeated by the descendants of Joseph. Therefore, the warriors of Simeon require the leadership of commanders from Manasseh, the grandson of Joseph, to guarantee their victory at Mount Seir [רד״ק].

Even though these commanders from Manasseh lead the successful conquest, they do not take any portion of the newly captured territory. The conquered land remains exclusively in the hands of the tribe of Simeon [מלבי״ם].