An Example: Halakhic Path of Gid HaNashe (the sciatic nerve)

(1) The prohibition of eating the sciatic nerve applies both in Eretz Yisrael and outside of Eretz Yisrael, in the presence of, i.e., the time of, the Temple and not in the presence of the Temple, and with regard to non-sacred animals and with regard to sacrificial animals. And it applies to domesticated animals and to undomesticated animals, to the thigh of the right leg and to the thigh of the left leg. But it does not apply to a bird, due to the fact that the verse makes reference to the sciatic nerve as being “upon the spoon of the thigh” (Genesis 32:33), and a bird has no spoon of the thigh. And the prohibition applies to a late-term animal fetus [shalil] in the womb. Rabbi Yehuda says: It does not apply to a fetus; and similarly, its fat is permitted. And butchers are not deemed credible to say that the sciatic nerve was removed; this is the statement of Rabbi Meir. And the Rabbis say: They are deemed credible about the sciatic nerve and about the forbidden fat.

(2) Although it is prohibited for Jews to eat the sciatic nerve, a Jewish person may send the thigh of an animal to a gentile with the sciatic nerve in it, without concern that the gentile will then sell the thigh to a Jew and the Jew will eat the sciatic nerve. This leniency is due to the fact that the place of the sciatic nerve is conspicuous in the thigh. One who removes the sciatic nerve must scrape away the flesh in the area surrounding the nerve to ensure that he will remove all of it. Rabbi Yehuda says: Scraping is not required; it is sufficient to excise it from the area above the rounded protrusion in order to thereby fulfill the mitzva of removal of the sciatic nerve.

(3) One who eats an olive-bulk of the sciatic nerve incurs forty lashes. If one eats an entire sciatic nerve and it does not constitute an olive-bulk, he is nevertheless liable to receive lashes, because a complete sciatic nerve is a complete entity. If one ate an olive-bulk from this sciatic nerve in the right leg, and an olive-bulk from that sciatic nerve in the left leg, he incurs [sofeg] eighty lashes. Rabbi Yehuda says: He incurs only forty lashes, for eating the olive-bulk from the right leg, and he is exempt for eating the olive-bulk from the left leg.

(4) In the case of a thigh that was cooked with the sciatic nerve in it, if there is enough of the sciatic nerve in it to impart its flavor to the thigh, the entire thigh is forbidden for consumption. How does one measure whether there is enough sciatic nerve to impart flavor to the meat of the entire thigh? One relates to it as though the sciatic nerve were meat imparting flavor to a turnip. If meat the volume of the sciatic nerve would impart flavor to a turnip the volume of the thigh when they were cooked together, then the entire thigh is forbidden.

(5) With regard to a sciatic nerve that was cooked with other sinews, when one identifies the sciatic nerve and removes it, the other sinews are forbidden if the sciatic nerve was large enough to impart flavor. And if he does not identify it, all the sinews are forbidden because each one could be the sciatic nerve; but the broth is forbidden only if the sciatic nerve imparts flavor to the broth. And similarly, in the case of a piece of an animal carcass or a piece of non-kosher fish that was cooked with similar pieces of kosher meat or fish, when one identifies the forbidden piece and removes it, the rest of the meat or fish is forbidden only if the forbidden piece was large enough to impart flavor to the entire mixture. And if he does not identify and remove the forbidden piece, all the pieces are forbidden, due to the possibility that each piece one selects might be the forbidden piece; but the broth is forbidden only if the forbidden piece imparts flavor to the broth.

(6) The prohibition of eating the sciatic nerve applies to a kosher animal and does not apply to a non-kosher animal. Rabbi Yehuda says: It applies even to a non-kosher animal. Rabbi Yehuda said in explanation: Wasn’t the sciatic nerve forbidden for the children of Jacob, as it is written: “Therefore the children of Israel eat not the sciatic nerve” (Genesis 32:33), yet the meat of a non-kosher animal was still permitted to them? Since the sciatic nerve of non-kosher animals became forbidden at that time, it remains forbidden now. The Rabbis said to Rabbi Yehuda: The prohibition was stated in Sinai, but it was written in its place, in the battle of Jacob and the angel despite the fact that the prohibition did not take effect then.

(7) One who removes the gid hanesheh must ferret out all traces of it until nothing remains. A butcher's word is accepted with regard to the gid hanesheh, just as it is accepted with regard to forbidden fat. [Accordingly,] we do not purchase meat from every butcher, [only from] an upright man who has established a reputation for observance. If he slaughters meat himself and sells it, his word is accepted.

(14) It is permitted to derive benefit from a gid hanesheh. Therefore it is permissible for a person to send a thigh which contains a gid hanesheh to a gentile. He may give him the entire thigh intact in the presence of a Jew. We do not suspect that [the other] Jew will partake of this meat before the gid is removed, because its place is recognizable. Accordingly, if the thigh was cut into pieces, he should not give it to a gentile in the presence of a Jew, lest the other Jew partake of it.

(2) It is from the roots of this commandment [that it is to serve as] a hint to Israel that though they will suffer many troubles in the exile by the hand of the nations and by the hand of the [descendants] of Esav (i.e. the Christians), [the Jews] should trust that they will not perish, but rather that their descendants and name will stand firm forever, and that their redeemer will come and redeem them from their oppressor. And in continually remembering this idea through the commandment that serves as a reminder, they will stand firm in their faith and righteousness forever. And this hint [stems from the fact that] that the angel who fought with Yaakov our forefather - who according to tradition (Bereshit Rabbah 78) was the guardian angel of Esav - wished to eliminate Yaakov from the world, he and his descendants; but he could not [get the better] of him, (Genesis 32:26) but anguished him in injuring his thigh. Likewise, Esav's seed anguishes the seed of Yaakov; but in the end, [the latter] will be saved from them. As we find (Genesis 32:32) with respect to [our] forefather that the sun shone to heal him and he was saved from pain, so will the sun of the messiah shine and he will heal us from our pain and redeem us speedily in our days, amen!