קהלת, פרק ה׳, פסוק ט״ז

The endless pursuit of wealth and material success often exacts a heavy physical and emotional price, stripping away a person's joy and peace of mind. The primary approach among commentators is that an individual can become so consumed by their business and the drive to gather money that they have no free time during daylight hours. Consequently, they are forced to delay their meals until the dark hours of the night [אבן עזרא, מצודת דוד]. Others suggest this darkness is emotional, representing meals eaten in sadness, or perhaps meals squeezed into the twilight hours—a restless time caught between the workday and the night's sleep [ביאור שטיינזלץ].

This immense burden inevitably leads to deep frustration. Managing a multitude of affairs guarantees that things will often fail to go as planned, resulting in constant anger [מצודת דוד]. This anger does not remain purely emotional. The commentators agree that such intense pressure and endless toil eventually cause actual physical illness [תעלומות חכמה, מצודת דוד, ביאור שטיינזלץ]. This physical breakdown is often accompanied by a mental toll, born from a state of constant fear and anxiety over one's wealth [אבן עזרא].

Eventually, this internal frustration and sickness boil over into outward outbursts [מצודת דוד, מצודת ציון]. In some cases, this eruption takes on a spiritual dimension. When a person suffers financial losses despite all their hard work, they may end up directing their bitter anger toward God [תעלומות חכמה].

Alongside this focus on the individual, a midrashic approach views this cycle as a historical picture of difficult times for the nation, such as the era of the Judges or the days of the Prophet Samuel. In this light, the darkness represents the overall gloom of the period. The anger reflects the evil deeds of the Israelites that provoked God, while the sickness represents the suffering that resulted from their actions. The final outburst of wrath captures the arrogant reaction of the people. Instead of taking responsibility for the sins that brought about their ruin, they complained and blamed God for their troubles [תורה תמימה].