Our Gemara on Amud Beis teaches us that there is a prohibition to offer the paschal sacrifice on a private altar.

Yitschok asks Esav to hunt and prepare game for him prior to bestowing the blessings of the first born upon him. In order to preempt Esav, Rivkah tells Yaakov to fetch two goats, which she will prepare as his father likes (Bereishis 27:9).

What is the significance of two goats? Rashi (ibid) explains that one goat was brought as a Paschal sacrifice and the other one was consumed.

Based on our Gemara, Maskil Ledovid asks how it was possible for Yitschok to bring a paschal sacrifice on a private altar. While there is some debate as to how literally and specifically the Patriarchs observed the precepts of the Torah (see Yoma 28b, Ramban Bereishis 26:5, and Ohr Hachaim Bereishis 49:3), the question here is bigger, because once the Avos took upon themselves a mitzvah, you would think that they would follow all its rules. Of what use is doing a paschal sacrifice in a non-prescribed manner? Let’s say Yitschok wanted to make a seder using rice cakes instead of matzah—would it have any value? The mitzvah would literally be “half-baked.” Maskil Ledovid answers that the prohibition only became effective after the Mishkan was established, so bringing a Paschal sacrifice on a private altar was fine. And since that was the appropriate mode of worship available, the question of it being a half mitzvah is mitigated.

The Maharal has a different approach regarding the Avos and mitzvos (Gur Aryeh Bereishis 46:10). He holds they fulfilled the positive commandments, but were not as bound by the prohibitions. This can be understood as follows: The positive commandments are actions of connection to God and personal elevation, and therefore the Avos wanted to take action in every way possible. The negative prohibitions are only meaningful when commanded—the abstention is about obedience and fear of God. If there is no command, there is no obedience. This is similar to the Ramban’s explanation for why a positive commandment overrides a prohibition (Shemos 20:8). If so, the prohibition against using a private altar was not binding.

Nonetheless, it does seem odd to ignore one aspect, even if a prohibition, while still fulfilling the mitzvah. Would Yitschok have chametz at his seder? However, we could answer that the prohibition of chametz is specific and directly tied to Pesach observance, while the prohibition against a private altar is not. This makes Yitschok’s Paschal sacrifice a little more congruent.

While reflecting on the choice of two goats, it occurred to me that perhaps these are reminiscent of the two goats on Yom Kippur, the inner chattas and the scapegoat. Ibn Ezra and Ramban (Vayikra 16:8) understand the Azazel goat as somehow giving the devil its due, a discharge of Esav’s energies. If so, Yaakov, who was taking Esav’s blessings, needed to tap into Esav’s energies; hence the two goats. Later, I was delighted to find that the Zohar (Bereishis 145a) says this explicitly:

“Herein foreshadowed the two he-goats which the children of Jacob were in the future to offer, one for the Lord and the other for Azazel on the Day of Atonement. We see Rivkah offering ‘two kids of the goats,’ one for the upper realm and the other to subdue Esav, so as to deprive him of any power over Yaakov.”