The sudden downfall of the Assyrian army at the gates of Jerusalem took place during a single night of a great miracle. God sent an angel or a supreme heavenly force to strike the camp, resulting in its total destruction [מצודת ציון]. This devastating blow was aimed directly at the military's chain of command. Not a single officer, deputy, or mighty warrior survived the night. The only individuals left alive were a handful of weak men who entirely lacked bravery or authority [רלב״ג, ביאור שטיינזלץ].
Following this decisive defeat, the Assyrian king was forced into an immediate retreat. Unable to accomplish anything against the city, he abandoned Jerusalem and returned to his own land deeply humiliated and disgraced [ביאור שטיינזלץ]. His ultimate fate served as a severe personal punishment for his towering arrogance and crimes. Later, while he was praying inside his temple of idol worship, he was violently murdered. The commentators agree that the assassins were his own biological offspring; specifically, his two sons formed a conspiracy against him and killed him with a sword [רש״י, מצודת דוד, ביאור שטיינזלץ].