A complete military and spiritual victory goes beyond merely winning on the battlefield; it requires overcoming the highest levels of enemy leadership. After defeating the opposing nations, the focus shifts to capturing their rulers alive and stripping away their freedom as the ultimate symbol of triumph [אבן עזרא, רד״ק, ביאור שטיינזלץ]. The captured kings and the highly respected nobles of these nations [מצודת דוד] are physically bound and imprisoned [מצודת ציון], locked away in heavy chains and strong iron shackles [מצודת ציון, מאירי].
Commentators offer different historical and spiritual lenses through which to view this capture. One approach connects these events to the original conquest of the land and the battles against the seven Canaanite nations. In this context, chaining the foreign kings was a necessary step to fulfill the Torah's Commandment to destroy them. Rather than being an act of cruelty, carrying out this judgment brings honor to the pious who faithfully obey God. They follow His will without letting flawed human reasoning interfere, standing in sharp contrast to King Saul, who mistakenly showed mercy to Agag, the king of Amalek [מלבי״ם].
Another perspective highlights the difference between various types of warfare. While the future war of Gog and Magog will be won miraculously through the praise of God without the need for physical weapons, the current events reflect the active military strategy of King David. David chose to personally pursue his enemies, take their kings captive, and carry out physical justice with his own hands, just as he did with the nation of Moab [אלשיך].
Beyond the literal events of the battlefield, the Talmud uses the concept of binding these foreign leaders as a legal memory aid. It serves to remind people which specific types of public structures Jews are forbidden to construct for idolatrous foreign kings [תורה תמימה].