Human existence is deeply fragile, a reality most sharply revealed when God brings suffering as a consequence of wrongdoing. When God corrects a person, the painful trials He delivers are always just and fair. These physical pains and disasters are sometimes understood as the specific warnings outlined in the Torah [רש״י], and they are always administered in exact proportion to the sin committed [מצודת דוד]. In reflecting on this divine discipline, the psalmist is actually looking inward, speaking directly about his own personal suffering [מאירי].
Under the weight of God's correction, the things a person values most begin to dissolve and decay, disappearing as rapidly as a moth eats through a garment. There are two primary ways to understand what is being consumed in this process. The first approach views this decay literally, explaining that a person's health, flesh, and bodily strength rot away through their suffering [רש״י, רד״ק, אבן עזרא, מאירי]. The second approach broadens this destruction to the material realm, suggesting that divine discipline wipes out a person's wealth and all the worldly possessions they hold dear [אלשיך, מצודת דוד, שטיינזלץ].
The sudden loss of physical vitality and material wealth leads to a stark conclusion about human life. Because the things people desire most can vanish as if they never existed, it becomes clear that all worldly actions and ambitions are ultimately empty [רד״ק, אבן עזרא, שטיינזלץ]. This reality is meant to serve as a constant warning, urging humanity to correct its path and return to God [מצודת דוד]. Tragically, even when people witness the suffering and financial ruin of their peers, they often fail to absorb the lesson, continuing to blindly chase the empty illusions of the world [אלשיך]. Conversely, internalizing the absolute nothingness of material pursuits can actually serve as a source of comfort. For the psalmist, recognizing that the physical world is merely an illusion brings profound relief from earthly anxieties and troubles [מאירי].