Two hips, two nerves, two types of mitzvos
וירא כי לא יכל לו ויגע בכף ירכו ותקע כף ירך יעקב בהאבקו עמו: על כן לא יאכלו בני ישראל את גיד הנשה וגו’ כי נגע בכף ירך יעקב בגיד הנשה
[The angel] saw that he could not overcome [Yaakov], so he touched the socket of his hip, and he dislodged the socket of Yaakov’s hip in his wrestling with him. Therefore, the Jewish people do not eat the sciatic nerve…for [the Angel] touched the socket of the hip of Yaakov, in his sciatic nerve
One of the more famous episodes of the Bible is the wrestling match between Yaakov and the Angel. The Torah describes him as an unknown man who attacked Yaakov unprovoked, and our Sages tell us this was the guardian Angel of Eisav, Yaakov’s brother. Yaakov was able to hold his own, so the Angel decided to fight dirty and dislocate Yaakov’s hip socket. In doing so, he affected Yaakov’s sciatic nerve. The Torah then testifies that this is the reason why it is forbidden for Jews to consume the sciatic nerve.
There’s an interesting dispute amongst our Sages regarding this prohibition. Rabbi Yehuda says that only the sciatic nerve of the right leg of an animal is forbidden, whereas the Rabbis say the sciatic nerves of both legs are forbidden. What is their underlying reasoning? The gemarra explains that Rabbi Yehuda holds that the Angel only hit Yaakov’s right leg, so only that sciatic nerve should become forbidden. However, the Rabbis say that he really snuck behind Yaakov and affected both legs, thus making them both forbidden. It’s interesting then that the two opinions are arguing about what actually transpired with Yaakov. We have a tradition that everything that happened to our forefathers portends what will transpire to their children. What then can we glean from this dispute whether the Angel struck only Yaakov’s right leg, or both his legs?
The guardian Angel of Eisav is also known as the Satan, or the Evil Inclination. His goal is to get the Jewish people to stray from the path of Hashem, and to poke holes in our perfect faith. The Torah tells us that the Angel saw it couldn’t overcome Yaakov. This means that he saw that Yaakov’s faith in Hashem was steadfast and couldn’t be negatively impacted. He therefore decided to strike Yaakov’s hip, representative of his future offspring. Meaning, the Angel made an effort to affect the future descendants of Yaakov and their faith.
If we analyze the mitzvos in the Torah, we’ll see that there are two classifications: Commandments between man and G-d, and interpersonal commandments. The Ten Commandments, which represent all of the 613 mitzvos, were divided into two tablets. The right tablet, containing five mitzvos between man and G-d, represented all such mitzvos. The left tablet, containing five interpersonal mitzvos, represent all such mitzvos.
There’s an interesting story about a potential convert who came to Hillel the Sage and asked him to be taught the entire Torah on one foot. His intent was that he only wanted to learn half of the Torah, the interpersonal mitzvos. Hillel responded that: “What is hateful to you, don’t do to others”. This principle summed up the entire corpus of interpersonal mitzvos. In contrast, a full and complete Jew is someone standing on two legs. Meaning, they incorporate into themselves both halves of the Torah: mitzvos between man and G-d, in addition to interpersonal mitzvos. However, someone lacking in one of these areas would be considered blemished. If they were lacking in mitzvos between man and G-d, they would be considered limping on their right leg. If they were lacking in interpersonal mitzvos, they would be considered limping on their left leg.
Now, the guardian Angel of Eisav was intending to attack Yaakov in both areas of the Torah. Yaakov was able to hold his ground and avoided all damage. This is why the Angel said that Yaakov succeeded in wrestling with both G-d and man, meaning he defended the mitzvos between man and G-d, and interpersonal mitzvos. Once the Angel saw that his plan was futile, he decided to aim for Yaakov’s descendants. He wanted to try to make future Jews weak in their fulfillment of the Torah.
If we were to analyze Torah observance in the past few centuries, we’ll see that the main area that people stopped keeping were mitzvos between man and G-d. However, interpersonal mitzvos like chesed and tzedaka have always been the hallmark of the Jewish people. Even the most secular Jew knows it’s important to give charity and help others. We can say then that they are limping on their right leg, as they are lacking in mitzvos between man and G-d. How history played out is alluded to in the opinion of Rabbi Yehuda. He held that the Angel only struck Yaakov’s right hip. Meaning, he was successful at weakening the observance of Yaakov’s descendants, but only in the area of mitzvos between man and G-d.
However, the Rabbis disagree. They held that if a person is lacking in their faith and devotion to G-d, then their interpersonal commitment will be inherently fleeting. It’s not as strong as it could be. The slightest wind can knock it away, and people can find all sorts of excuses not to help others. This is alluded to in the words of the Rabbis that the Angel “snuck behind Yaakov”. Meaning, from the front it would appear that only the right hip was affected. However, upon careful examination we’ll see that the left one was as well. People outwardly could appear generous with others, but on the inside may not be as motivated and enthusiastic as they could be.
Now we can properly understand why both sciatic nerves are forbidden.
 Based on Be’er Yosef to Genesis 32:26,33
 Genesis loc. cit.
 Bereishis Rabbah 77:3, brought by Rashi to v. 25
 Chullin 90b
 Ibid 91a
 כל מה שאירע לאבות סימן לבנים (Ramban to Genesis 12:6, his source being Midrash Tanchuma Lech Lecha § 9)
 See Bava Basra 16a and Ohr HaChaim to Deuteronomy 19:11
 He struck his ירך, and offspring are often referred to as יוצאי ירכו (Genesis 46:26)
 See Bereishis Rabbah 77:3 and Zohar Chadash end of parshas Noach. This explanation also appears in Akeidas Yitzchak ad. loc.
 See Rashi to Exodus 24:12, quoting Rav Saadiah Gaon. See also Ba’al HaTurim, to Exodus 20:14, quoting Bamidbar Rabbah 13:16
 Ramban to Exodus 20:13-14. Honoring one’s father and mother is considered honoring Hashem (see Kiddushin 30b). See also Beis Elokim Sha’ar HaYesodos Chapter 12
 Shabbos 31a
 The Be’er Yosef records that he saw this interpretation of the gemarra in some sefer. It would seem the name escaped him
 Genesis 32:29