The Midrash tells us that what impressed Isaac, was not the scent of Jacob’s garments (bigadim), rather it was the spiritual character of his betrayers (bogdim), those descendants of Jacob who would turn away from God and then turn back again in repentance. It was through this that Isaac found Jacob worthy of his blessing.
The Midrash relates the story of Joseph Meshita, a Jew who helped the Romans in their destruction of the Temple. As his reward, the Romans said he could go into the Temple and take out whatever he wanted. Joseph came out with the gold menorah. When the Romans saw this, they told him that it was far too precious, and he should go back in and select something else. Joseph refused saying “Is it not enough that I have angered my God once, that I should now anger him a second time?”
Joseph was tortured by the Romans but he did not back down, and he died in complete repentance.
However, we must ask why it is that Isaac focused on a traitor as a justification to bless Jacob, rather than one of the righteous — a prophet or great rabbi?
The reason is that the ability to climb from the lowest depths and return to God in repentance, as Joseph Meshita did, is the true hallmark of the Jewish people. We have our great righteous individuals and Torah giants, but the one thing that defines us all is that spark of spiritual strength which allows us to reach from the depths to connect with God and return to Him wholeheartedly, no matter how far we have fallen — and that is worthy of a blessing.