פירוש על דברי הימים ב 11:1

and he assembled the house of Judah and Benjamin who were together on the border. Jerusalem belonged to both of them, and the Temple was built on their common border. In the section dealing with boundaries in Joshua, it explains how their border was shared. Our Rabbis also said (Yoma 12a, Meg. 26a, Zeb. 53b): A strip protruded from the territory of Benjamin and entered the territory of Judah, upon which the altar was built. Therefore, they were inseparable, and they are also mentioned close to one another.