The capture of Jerusalem and the fortress of Zion was not achieved through a prolonged siege, but rather through a sudden, decisive military strike aimed at breaching the fortified city [ביאור שטיינזלץ]. As David faced both imposing physical walls and the psychological warfare of the city's inhabitants, he issued a bold challenge to his men. He promised a profound reward to the first warrior to strike the Jebusites. While the exact prize was left unstated in the heat of the moment, it was understood that the victor would be appointed chief and commander of the army, a prestigious rank ultimately claimed by Joab, the son of Zeruiah [רש״י, רד״ק, מצודת דוד, מלבי״ם, ביאור שטיינזלץ].
The central target of this assault was a strategic and highly fortified vulnerability within the city. The primary approach among commentators identifies this as either a towering stronghold where the Jebusites placed their confidence [רש״י, מצודת דוד, מצודת ציון], or a critical water shaft supplying the city [ביאור שטיינזלץ]. Another perspective suggests it was a conduit channeling water over idolatrous statues [מלבי״ם], while a metaphorical interpretation views the target as the ancestral lineage of the ancient king Abimelech [אלשיך]. David outlined a carefully staged tactical assault: first, his men were to defeat the Jebusite soldiers, then dismantle this strategic structure, and finally eliminate what the defenders referred to as the "blind and the lame" [מלבי״ם, מצודת דוד].
These "blind and the lame" were central to the city's psychological defense. According to tradition, the Jebusites claimed descent from Abimelech and forged copper statues inscribed with the ancient oath of peace he had sworn with Abraham and Isaac. By placing these idols on the walls, they hoped to deter David's advance. Recognizing that the oath's validity had long expired, David commanded his forces to strike the structural supports so the statues would collapse on their own, sparing his men from direct contact with them [מצודת דוד]. He also dismissed any lingering hesitation regarding the oath by pointing out that the vast majority of the city's inhabitants were not actually of Abimelech's lineage [אלשיך]. The breach itself was marked by extraordinary feats; Joab vaulted over the wall using a bent cypress tree, while God miraculously lowered the fortifications to aid David's entry [רד״ק, אלשיך].
The defenders and their deterrents were deeply despised by David. This intense aversion was directed either at the Jebusites themselves for their arrogant mockery [מצודת דוד, רד״ק], at the entire defensive array [מלבי״ם], or specifically at the statues due to their idolatrous nature [אלשיך]. The dramatic conquest culminated in a lasting decree that "the blind and the lame shall not enter the house." This served either as a humiliating regulation barring Jebusites from the royal palace and the fortress of Zion as a permanent memorial of the victory [מצודת דוד, רד״ק, ביאור שטיינזלץ, מלבי״ם], or as a severe warning to the Israelites never to bring idolatrous statues into their own homes [אלשיך].