Human existence is profoundly fragile, making any reliance on mortal strength ultimately pointless. The primary approach among commentators is that this reality serves as a warning against placing our trust in people, as human life is fleeting and inherently unstable [אבן עזרא, מצודת דוד, ביאור שטיינזלץ]. Conversely, this fragility also offers comfort. Instead of a warning against misplaced trust, it can be understood as a call not to fear others, since God remains the only true refuge in times of distress [רש״י]. In a broader sense, this means there is no reason to be intimidated by the wealth, health, and success of opposing nations during times of exile, because their prosperity is strictly temporary [מאירי].
When evaluating humanity, a distinction is drawn between different types of individuals. One perspective divides them by social standing, contrasting the ordinary, simple masses with the great and important figures of society [מלבי״ם]. Another viewpoint sees a historical division. It contrasts the early generations who relied on the merit of the first man and perished in the flood, with the later generation of the dispersion who mistakenly relied on the merit of Noah, who was known as a righteous man [אלשיך].
Regardless of status or history, human reliability is fundamentally flawed. The failure of human promise is not necessarily a deliberate lie, but rather an inability to endure over time. Much like a natural spring that eventually dries up and stops providing water, human guarantees are temporary [רד״ק, מאירי, אלשיך]. Therefore, even when the commitments made by powerful and important individuals appear completely stable and trustworthy in the moment, they will inevitably fail and lead to disappointment [מלבי״ם].
To illustrate this lack of substance, a poetic image of a balancing scale is used. The primary approach among commentators suggests that if all of humanity—or all the trust we place in them—were placed on one side of a scale, and absolute emptiness or a mere breath were placed on the other, humanity would prove to be lighter. The side holding people would rise upward because of its lack of substance, while the sheer emptiness would outweigh them and sink [רד״ק, אבן עזרא, מצודת דוד, ביאור שטיינזלץ, מאירי]. Even if all people were to join forces and act in perfect unity, as they did when building the Tower of Babel, their collective effort carries no actual weight or lasting presence before God [אלשיך]. A simpler interpretation of this imagery suggests that if all people were weighed together, the results would simply reveal that their inherent emptiness is entirely equal [רש״י].