Korach's sons, however, who had plotted the rebellion together with their father and Dathan and Aviram, did not die.
Korach's sons...did not die
Korach's sons played a key role in his rebellion, and to all outward appearances were full participants in it. This is why, to all appearances, they indeed suffered the same fate as the rebels. But because they repented in their hearts, they were spared the death penalty and allowed later to resume their lives in the community. Had they acted on their regret, they would have been spared even this lesser punishment.
This shows us the tremendous power of repentance--even when it is not acted upon as should be.
This insight should quiet any doubts that we may have about the possibility of redemption in our times. We are taught that "when the Jewish people repent, they will be immediately redeemed." But even merely thinking about repenting is sufficient to bring about the final redemption--especially when this is added to the merits we have accrued through our protracted exile: the Torah we have studied, the commandments we have performed, and the martyrdom we have suffered.
From the Kehot
Chumash Synagogue Edition