The downfall of the wicked often unfolds with perfect justice, where the very plans designed to harm others become the cause of their own destruction. The approaching disaster is aimed at a single target, which commentators understand in a few different ways. Some suggest it applies to each enemy individually or to the hostile group as a single unit [רד״ק, אבן עזרא, מאירי]. Others focus on a specific historical figure, identifying the enemy as King Saul during his relentless hunt for David [רד״ק, אלשיך].
The disaster that strikes is viewed in complementary ways. It is described as a state of complete darkness [רש״י, מצודת ציון], as well as a sudden, heavy defeat and panic that will shock anyone who hears about it [רד״ק, שטיינזלץ, אבן עזרא]. Faced with this sudden ruin, the enemy is left entirely helpless. Because the trouble arrives without warning or emerges from complete darkness, he will not feel it coming, understand where it came from, or know how to escape it [רד״ק, שטיינזלץ, מצודת דוד].
A hunter naturally hides his net under dirt or straw so that a passerby will not notice the danger [רש״י, מצודת דוד]. However, a principle of exact payback takes effect [מאירי]. Blinded by the sudden darkness and chaos, the enemy will fail to see the very trap he carefully prepared for his victim, and he will stumble directly into it [מצודת דוד, שטיינזלץ].
This reversal carries deep psychological and spiritual meaning, particularly regarding King Saul. Initially, Saul will not view his disaster as a punishment for hunting David, because he genuinely believed his actions were right. While it normally takes many hardships to force a person to recognize their wrongdoing, Saul's experience will be different. Being caught in his own trap and defeated in the exact way he used to hunt David will serve as a single, powerful blow. This specific downfall will make him realize that it is God's angel pursuing him, leading him to finally admit his sin and change his ways [אלשיך].