We normally shun deception and trickery. Yaakov, however, had to put them to good use to obtain the berachah. Using them amounted to an aveirah lishmah, which Chazal tell us is considered the equivalent of a mitzvah – albeit only as good as a mitzvah performed not for the sake of Heaven.
The two Yom Kippur goats demonstrate this. One of them becomes the focus of a complex and elegant avodah performed on the holiest day of the year in the holiest place on earth. The treatment of the other goat is tainted. To the untrained eye, it looks like a form of pagan spirit-worship. Yet, it too becomes a mitzvah when Hashem commands that it be done. Part of the message is certainly that any seemingly ungodly forces, kochos of pollution and tumah, owe their existence entirely to His Will.
Rivkah meant to convey this point to Yaakov, according to our medrash. The “two” meant to underscore an essential duality in what she asked of her son, similar to the tension between the two goats of Yom Kippur. On the one hand, he would be performing a mitzvah of honoring his mother. On the other, he would be deceiving his father. Both would be necessary to attain the berachah.
We find that Yaakov was punished for causing pain to his brother. Eisav’s “great and bitter cry” inexorably led to the “great and bitter cry” by Yaakov’s descendants in the days of Esther. We do not see, however, that Yaakov was punished for the awful, great fright that he caused Yitzchok when he realized that he had been deceived. Why is Yaakov punished for the pain he inflicted upon Eisav but not for the fright he caused his father?
We are told that we ought to perform mitzvos even shelo lishmah. On some level, a mitzvah always remains a positive accomplishment, regardless of the way it is done. Not so in regard to an aveirah. On those occasions when performing an aveirah can be justified, it must be done entirely lishmah. Any admixture of self-serving benefit remains an aveirah.
Yaakov’s deception of his father was a justifiable aveirah. It immediately caused pain to two people. Yaakov could not be blamed for Yitzchok’s fright. It was unavoidable; under the circumstances, Yaakov was considered as if acting beyond his control. Yaakov gained nothing from the pain he caused his father. To the contrary, we must assume that he himself was pained by it.
Eisav’s cry was a different matter. While Yaakov was justified (and therefore not legally culpable) for causing it, bringing it about was not entirely lishmah. Yaakov was not unhappy about it. He took secret satisfaction in it.
For that, he was punished.
