In Parshas Nitzavim, Moshe Rabbeinu relates the words of Hashem to the Bnei Yisroel:
“Perhaps there is among you a man, woman, family, or tribe, whose heart strays this day from Hashem to go and worship Avodah Zarah. Perhaps there is among you a root that produces hemlock and wormwood.” (Devarim 29:17)
“And it will be, when he [such a person] hears the words of these sanctions, that he will bless himself in his heart, saying, ‘I will have peace, even if I follow my heart's desires,’...” (Devarim 29:18)
“Hashem will not be willing to forgive him; rather, Hashem’s fury and zeal will fume against that man, and the entire curse written in this book will fall on him...” (Devarim 29:19)
The Ramban explains that the first Passuk above, refers to two different people. The first part of the Passuk refers to a man who has already decided to worship Avodah Zarah. The second part of the Passuk refers to someone who has made no such decision but has within him a rotten root or core which if left unchecked, will lead to the worship of Avodah Zarah. When each of these people hear the curse that is to come, they will both think that the curses will not apply to them and that they will have complete peace (2nd Passuk above). The Torah is informing them that this will not be the case, and that they will both incur punishment (3rd Passuk above). Regarding the second person who has not done anything wrong, the sole distinction between him and the rest of that lofty generation (the, “Dor Dai’ah” – generation in the desert that frequently saw Hashem’s open miracles) is that deep inside he has a rotten root that, in the future will affect his descendants [causing them to worship Avodah Zarah. This can be true with any Middah that is left to fester].
We see that tolerance for bad Middos is like a tiny seed of corruption that, if left unattended, takes root deep within the soul. It festers and grows, twisting and warping one's character until it casts a long, dark shadow that can touch the lives of generations to come.
The Ramban and the Passukim above reveal a chilling truth about this internal rot: it possesses a deceptive power, whispering lies that can convince us that we can escape the consequences of our actions. As the Passuk above says, his internal voice deceives him and he says, “I will have peace, even if I follow my heart's desires.”
But there is hope. The fact that Hashem punishes such individuals signifies their capacity to correct their Middos, as we know Hashem does not punish to take retribution but rather to correct. Accordingly, Hashem meting out punishment, must be a sign that these individuals have the power to change their ways, to purify themselves and emerge stronger. As the Gemorah in Shabbos 104a tells us, “Haba LeTaher – MeSayin Osso” - when we genuinely seek to cleanse our souls, we receive Divine assistance to make it happen.