דברי הימים ב, פרק ח׳, פסוק ה׳

King Solomon actively worked to strengthen his kingdom through strategic building and fortification projects. As part of this broader effort, he transformed the settlements of Upper and Lower Beth-horon into highly protected strongholds. These locations were originally established by Sheerah from the tribe of Ephraim. However, Solomon's contribution involved either rebuilding the towns after they had fallen into ruin or significantly upgrading them from simple rural villages into heavily fortified, walled cities [מצודת דוד, ביאור שטיינזלץ].

The necessity for such massive fortifications stemmed directly from the geographic placement of these cities along the border of the territory [רש״י]. By establishing firm control over these specific areas, Solomon could effectively monitor the main travel routes. Furthermore, these fortresses served as a clear symbol of royal authority, reflecting his ongoing efforts to unite the entire kingdom and bring it firmly under his leadership [ביאור שטיינזלץ].

The resulting strongholds were built with such exceptional strength that an invading enemy would find it impossible to simply breach their defenses. Instead, an opposing army would be forced to lay a prolonged siege around the perimeter, attempting to cut off the supply of food and water [מצודת ציון]. This extraordinary level of security was achieved by outfitting the cities with massive walls, heavy double doors, and sturdy bars [ביאור שטיינזלץ].