The generation that left Egypt faced a tragic end, living out their final years in constant wandering and fear rather than finding peace and fulfilling their ultimate purpose. The primary approach among commentators is that God imposed this fate after the sin of the spies. The Israelites were sentenced to roam the desert for forty years until every person aged twenty and older passed away, never stepping foot in the Land of Israel [רד״ק, מצודת דוד, ביאור שטיינזלץ]. Because the entire goal of leaving Egypt was to reach this destination, failing to do so meant their lives concluded in complete emptiness [אבן עזרא]. Other perspectives suggest this futile existence also reflects the punishment of the children who were forced to live as desert nomads, or the tragic deaths caused by venomous serpents [מלבי״ם, אלשיך].
When their lives did end, it was not through a quiet, natural passing [ביאור שטיינזלץ]. The language points to a specific, recognized terror, suggesting a devastating plague that struck the camp or the sudden demise of the spies themselves [רד״ק, מאירי]. Alternatively, this terror describes the tragedy of premature death, as many died before the forty years were over [אבן עזרא]. Another view proposes a division between the generations, where the children were doomed to wander while the fathers collapsed and died in fear in the wilderness [מלבי״ם].
Beyond physical death, the punishment carried a profound psychological weight. For those who had only a few days left before reaching the end of their allotted time, death came swiftly. However, those who still had years left to live endured constant, crushing anxiety. Every year on the night of the Ninth of Av, the people would dig their own graves and sleep inside them, uncertain if it was their night to die. Even when they awoke the next morning to find themselves alive, the relief was only temporary. They spent the rest of the year living in daily dread, waiting in fear for the next Ninth of Av to arrive [אלשיך].