The return to the Land of Israel brings a powerful warning drawn directly from history. The people are urged to learn from the tragic mistakes of past generations and avoid repeating the errors that led to disaster. The primary approach among commentators is that the ancestors in question are specifically those who lived during the era when the First Temple was destroyed. In those days, the earlier prophets constantly warned the people, urging them to abandon their harmful ways and return to God. Tragically, those ancestors stubbornly refused to listen.
While the immediate consequence of ignoring these warnings was divine punishment, a deeper historical perspective reveals a more specific threat [אברבנאל]. The primary danger was not physical afflictions like famine or disease, but rather the devastating reality of exile. It was this very refusal to heed the prophets that caused the Ten Tribes to be banished to Assyria and scattered the people of Jerusalem across the globe. Now that the nation has finally returned to the Holy Land, they must be exceptionally careful. Repeating the stubbornness of their ancestors could easily trigger yet another destruction.
Furthermore, the specific mention of these earlier prophets carries a profound hint about the future. The era of prophecy is destined to come to a close during the time of the Second Temple. The people are being warned that they will not always have prophets walking among them to offer guidance and correction. Therefore, the moral responsibility to observe the laws of God—laws that are eternal and unchanging—will soon rest completely on their own shoulders. They must actively choose to turn away from bad deeds and return to Him, relying on their own inner conviction rather than waiting for a prophet's rebuke.