Korban Pesach and the Gid HaNasheh

This source sheet serves as a basis for a Chaburah on the interplay between the Mitzvah of eating the Korban Pesach and the prohibition of Gid HaNasheh (GH), the sciatic nerve. Specifically, the tension between the imperatives to both fully roast the Korban Pesach and completely consume its flesh (without leftover) and the prohibition against eating the GH, i.e. a limitation on consuming the entirety of the Korban. This tension between the two directives gives rise to two discussion among the traditional commentators of the Talmud and Halachik Codes.

First, which is the topic of this source sheet, is whether a person must remove the GH prior to roasting the Korban Pesach or can he roast the entire Korban and only remove the GH first when eating the Korban? Second, given the Mitzvah to eat the Korban Pesach why does that not push aside the prohibition against eating the GH (in Talmudic nomenclature: עשה דוחה לא תעשה)?

The source sheet is laid out as follows:

  1. We will first layout some of the basic sources for the Mitzvah of Korban Pesach and the prohibition on GH as they relate to this discussion.
  2. We will then layout some additional sources that various commentators have found relevant to the discussion.
  3. We will then introduce via primary sources, the dispute as to whether one may roast the Korban Pesach with the GH intact.
  4. We will then introduce the classical understanding of the party allowing the Korban Pesach to be roasted with the GH intact.
  5. We will then, based on the various sources already reviewed, introduce a number of other approaches to the dispute.

*Source sheet note: English Translations unless otherwise noted are from Sefaria. Copies of the Seforim inserted in the source sheet all come from Hebrewbooks.org (highlighting by me).

Any questions, comments or concerns may be addresed to [email protected].

Part 1

Basic Sources

This is the basic text establishing the Mitzvah of the Korban Pesach. On the first of Nissan, Hashem commands Moshe to instruct Bnei Yisroel to prepare for their imminent departure from Egypt. As part of their preparation they are to take a lamb and slaughter it on the afternoon of the 14th of Nissan and smear the blood on their doorposts. That evening, they are to roast the animal and completely consume its flesh, without leftovers.

(א) וַיֹּ֤אמֶר יי אֶל־מֹשֶׁ֣ה וְאֶֽל־אַהֲרֹ֔ן בְּאֶ֥רֶץ מִצְרַ֖יִם לֵאמֹֽר׃ (ב) הַחֹ֧דֶשׁ הַזֶּ֛ה לָכֶ֖ם רֹ֣אשׁ חֳדָשִׁ֑ים רִאשׁ֥וֹן הוּא֙ לָכֶ֔ם לְחָדְשֵׁ֖י הַשָּׁנָֽה׃ (ג) דַּבְּר֗וּ אֶֽל־כָּל־עֲדַ֤ת יִשְׂרָאֵל֙ לֵאמֹ֔ר בֶּעָשֹׂ֖ר לַחֹ֣דֶשׁ הַזֶּ֑ה וְיִקְח֣וּ לָהֶ֗ם אִ֛ישׁ שֶׂ֥ה לְבֵית־אָבֹ֖ת שֶׂ֥ה לַבָּֽיִת׃ (ד) וְאִם־יִמְעַ֣ט הַבַּיִת֮ מִהְיֹ֣ת מִשֶּׂה֒ וְלָקַ֣ח ה֗וּא וּשְׁכֵנ֛וֹ הַקָּרֹ֥ב אֶל־בֵּית֖וֹ בְּמִכְסַ֣ת נְפָשֹׁ֑ת אִ֚ישׁ לְפִ֣י אָכְל֔וֹ תָּכֹ֖סּוּ עַל־הַשֶּֽׂה׃ (ה) שֶׂ֥ה תָמִ֛ים זָכָ֥ר בֶּן־שָׁנָ֖ה יִהְיֶ֣ה לָכֶ֑ם מִן־הַכְּבָשִׂ֥ים וּמִן־הָעִזִּ֖ים תִּקָּֽחוּ׃ (ו) וְהָיָ֤ה לָכֶם֙ לְמִשְׁמֶ֔רֶת עַ֣ד אַרְבָּעָ֥ה עָשָׂ֛ר י֖וֹם לַחֹ֣דֶשׁ הַזֶּ֑ה וְשָׁחֲט֣וּ אֹת֗וֹ כֹּ֛ל קְהַ֥ל עֲדַֽת־יִשְׂרָאֵ֖ל בֵּ֥ין הָעַרְבָּֽיִם׃ (ז) וְלָֽקְחוּ֙ מִן־הַדָּ֔ם וְנָֽתְנ֛וּ עַל־שְׁתֵּ֥י הַמְּזוּזֹ֖ת וְעַל־הַמַּשְׁק֑וֹף עַ֚ל הַבָּ֣תִּ֔ים אֲשֶׁר־יֹאכְל֥וּ אֹת֖וֹ בָּהֶֽם׃ (ח) וְאָכְל֥וּ אֶת־הַבָּשָׂ֖ר בַּלַּ֣יְלָה הַזֶּ֑ה צְלִי־אֵ֣שׁ וּמַצּ֔וֹת עַל־מְרֹרִ֖ים יֹאכְלֻֽהוּ׃ (ט) אַל־תֹּאכְל֤וּ מִמֶּ֙נּוּ֙ נָ֔א וּבָשֵׁ֥ל מְבֻשָּׁ֖ל בַּמָּ֑יִם כִּ֣י אִם־צְלִי־אֵ֔שׁ רֹאשׁ֥וֹ עַל־כְּרָעָ֖יו וְעַל־קִרְבּֽוֹ׃ (י) וְלֹא־תוֹתִ֥ירוּ מִמֶּ֖נּוּ עַד־בֹּ֑קֶר וְהַנֹּתָ֥ר מִמֶּ֛נּוּ עַד־בֹּ֖קֶר בָּאֵ֥שׁ תִּשְׂרֹֽפוּ׃ (יא) וְכָכָה֮ תֹּאכְל֣וּ אֹתוֹ֒ מָתְנֵיכֶ֣ם חֲגֻרִ֔ים נַֽעֲלֵיכֶם֙ בְּרַגְלֵיכֶ֔ם וּמַקֶּלְכֶ֖ם בְּיֶדְכֶ֑ם וַאֲכַלְתֶּ֤ם אֹתוֹ֙ בְּחִפָּז֔וֹן פֶּ֥סַח ה֖וּא לַיי

(1) The LORD said to Moses and Aaron in the land of Egypt: (2) This month shall mark for you the beginning of the months; it shall be the first of the months of the year for you. (3) Speak to the whole community of Israel and say that on the tenth of this month each of them shall take a lamb to a family, a lamb to a household. (4) But if the household is too small for a lamb, let him share one with a neighbor who dwells nearby, in proportion to the number of persons: you shall contribute for the lamb according to what each household will eat. (5) Your lamb shall be without blemish, a yearling male; you may take it from the sheep or from the goats. (6) You shall keep watch over it until the fourteenth day of this month; and all the assembled congregation of the Israelites shall slaughter it at twilight. (7) They shall take some of the blood and put it on the two doorposts and the lintel of the houses in which they are to eat it. (8) They shall eat the flesh that same night; they shall eat it roasted over the fire, with unleavened bread and with bitter herbs. (9) Do not eat any of it raw, or cooked in any way with water, but roasted—head, legs, and entrails—over the fire. (10) You shall not leave any of it over until morning; if any of it is left until morning, you shall burn it. (11) This is how you shall eat it: your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it hurriedly: it is a passover offering to the LORD.

As he returns to Eretz Canaan and anticipating a meeting with his brother, Yaakov encounters Esau's archangel who strikes him on his hip resulting in a limp. To recall this incident, the Bnei Yisroel are forever enjoined from consuming the Gid HaNasheh.
(לג) עַל־כֵּ֡ן לֹֽא־יֹאכְל֨וּ בְנֵֽי־יִשְׂרָאֵ֜ל אֶת־גִּ֣יד הַנָּשֶׁ֗ה אֲשֶׁר֙ עַל־כַּ֣ף הַיָּרֵ֔ךְ עַ֖ד הַיּ֣וֹם הַזֶּ֑ה כִּ֤י נָגַע֙ בְּכַף־יֶ֣רֶךְ יַעֲקֹ֔ב בְּגִ֖יד הַנָּשֶֽׁה׃

(33) That is why the children of Israel to this day do not eat the thigh muscle that is on the socket of the hip, since Jacob’s hip socket was wrenched at the thigh muscle.

This Mishna sets out the basic parameters of the prohibition against the Gid Hanasheh. Note that the Gid is prohibited even in Korbonos.

(א) גִּיד הַנָּשֶׁה נוֹהֵג בָּאָרֶץ וּבְחוּצָה לָאָרֶץ, בִּפְנֵי הַבַּיִת וְשֶׁלֹּא בִפְנֵי הַבַּיִת, בְּחֻלִּין וּבְמֻקְדָּשִׁים. וְנוֹהֵג בִּבְהֵמָה וּבְחַיָּה, בְּיָרֵךְ שֶׁל יָמִין וּבְיָרֵךְ שֶׁל שְׂמֹאל. וְאֵינוֹ נוֹהֵג בְּעוֹף, מִפְּנֵי שֶׁאֵין לוֹ כָף....

(1) [The prohibition against eating] the sciatic nerve applies in the land [of Israel] and outside of the land, during the time of the Temple and not during the time of the Temple, for chulin [animals or food permitted for general consumption] and for mukdashim [animals or food which are holy and not available for general consumption]. And it applies to domesticated and wild animals, for the right thigh and the left thigh. But it does not apply to a bird since it does not have a spoon [shaped hip]. ...

The Korban Pesach is unique in that the rules regarding when it can be eaten, who can eat it and how it must be eaten are unique as well. They are succinctly listed in our Mishna. First, even though it has to be slaughtered during the day, it may only be eaten during a very limited window of time, between nightfall and midnight following its slaughter. Second, participation in the Korban requires forethought and planning and not randomness and carelessness. Therefore, only those people who join the group prior to the Korban being slaughtered may participate. Finally, it may only be roasted and cannot be cooked or eaten raw, you cannot break a bone and it must be eaten alongside Matzoh and Marror.Translation of the following Mishna is mine.
  1. (a) הבכור. והמעשר. והפסח. קדשים קלים.
    (b) שחיטתן בכל מקום בעזרה.
    (c) ודמן טעון מתנה אחת. ובלבד שיתן כנגד היסוד.
  2. שינה באכילתן.
    (a) הבכור נאכל לכהנים.
    (b) והמעשר לכל אדם.
    (c) ונאכלין בכל העיר לכל אדם. בכל מאכל. לשני ימים ולילה אחד.
  3. (a) הפסח אינו נאכל אלא בלילה.
    (b) ואינו נאכל אלא עד חצות.
    (c) ואינו נאכל אלא למנויו.
    (d) ואינו נאכל אלא צלי:
  1. (a) [Each of] the Bechor, Ma'aser B'Heima and the Pesach [fall within the category of] Kodshim Kalim.
    (b) their slaughtering may take place anywhere in the Azarah
    (c) and their blood requires but a single application so long as it is applied near the base of the Mizbeach
  2. [However,] they differ in how they are consumed:
    (a) the Bechor is eaten solely by Kohanim
    (b) [whereas,] the Ma'aser [may be consumed] by all people
    (c) both [the Bechor and Ma'aser] may be consumed (i) anywhere in Yerushalayim, (ii) by anyone (i.e., there is no need for a Chaburah), (iii) cooked in any fashion, and (iv) for two days and the intervening night.
  3. The Pesach, [however,] cannot be consumed except [under the following conditions]:
    (a) During the evening following its slaughter;
    (b) up until midnight;

    (c) by the members of the prearranged group
    (d) when roasted.
This Mishna describes the roasting process for the Korban Pesach.

(א) כֵּיצַד צוֹלִין אֶת הַפֶּסַח, מְבִיאִין שַׁפּוּד שֶׁל רִמּוֹן, תּוֹחֲבוֹ מִתּוֹךְ פִּיו עַד בֵּית נְקוּבָתוֹ, וְנוֹתֵן אֶת כְּרָעָיו וְאֶת בְּנֵי מֵעָיו לְתוֹכוֹ, דִּבְרֵי רַבִּי יוֹסֵי הַגְּלִילִי. רַבִּי עֲקִיבָא אוֹמֵר, כְּמִין בִּשּׁוּל הוּא זֶה, אֶלָּא תוֹלִין חוּצָה לוֹ:

(1) How must we roast the Pesach sacrifice ? We bring a spit [made of the wood] of a pomegranate-tree and jab it in at its mouth [of the lamb or kid] until [it comes out again at] the place of its [lower] opening; and one places its legs and its entrails inside of it - so says Rabbi Yose Haglili. Rabbi Akiva says, "This would be a kind of boiling; rather we suspend them outside [of the lamb]."

Part 2

Additional Sources

The end of the following Mishna describes a dispute between the Chachomim and Rabi Yehudah over whether the prohibition on the Gid HaNasheh existed prior to the giving of the Torah on Har Sinai.

(ו) נוֹהֵג בִּטְהוֹרָה, וְאֵינוֹ נוֹהֵג בִּטְמֵאָה. רַבִּי יְהוּדָה אוֹמֵר, אַף בִּטְמֵאָה. אָמַר רַבִּי יְהוּדָה, וַהֲלֹא מִבְּנֵי יַעֲקֹב נֶאֱסַר גִּיד הַנָּשֶׁה, וַעֲדַיִן בְּהֵמָה טְמֵאָה מֻתֶּרֶת לָהֶן. אָמְרוּ לוֹ, בְּסִינַי נֶאֱמַר, אֶלָּא שֶׁנִּכְתַּב בִּמְקוֹמוֹ:

(6) [The prohibition against eating the sciatic nerve] applies for permitted [animals] but does not apply for prohibited ones. Rabbi Yehuda says, "Even for prohibited ones." Said Rabbi Yehuda,"For from the [time of] the sons of Ya'akov the sciatic nerve was forbidden, and prohibited animals were still permitted to them." They said to him, "[The prohibition] was stated at Sinai, but it was written [about] in its place."

This Mishna describes the differences between the original Korban Pesach brought in Egypt and the one brought throughout the generations. Is this a complete list?

(ה) מַה בֵּין פֶּסַח מִצְרַיִם לְפֶסַח דּוֹרוֹת, פֶּסַח מִצְרַיִם מִקָּחוֹ מִבֶּעָשׂוֹר, וְטָעוּן הַזָּאָה בַאֲגֻדַּת אֵזוֹב עַל הַמַּשְׁקוֹף וְעַל שְׁתֵּי מְזוּזוֹת, וְנֶאֱכָל בְּחִפָּזוֹן בְּלַיְלָה אֶחָד, וּפֶסַח דּוֹרוֹת נוֹהֵג כָּל שִׁבְעָה:

(5) What is the difference between Pesach [celebrated] in Egypt, and Pesach [observed] by [later] generations? The Pesach [sacrifice] in Egypt [required that] its purchase be on the tenth [of Nissan]; and required the sprinkling of its blood with a bunch of hyssop on the lintel, and on the two side-posts [of entrances]; and that it be eaten in one night in haste; whilst Pesach of [later] generations, was observed for all seven [days].

The following Mishna and Gemara discuss the situation whereby one inadvertently cooked a piece of meat with the GH remaining inside.

(ד) יָרֵךְ שֶׁנִּתְבַּשֵּׁל בָּהּ גִּיד הַנָּשֶׁה, אִם יֶשׁ בָּהּ בְּנוֹתֵן טַעַם, הֲרֵי זוֹ אֲסוּרָה. כֵּיצַד מְשַׁעֲרִין אוֹתָהּ. כְּבָשָׂר בְּלָפֶת:

(4) A thigh in which the sciatic nerve was cooked, if it has [enough] to give flavor [to the thigh], this [thigh] is forbidden. How do we measure it? Like meat [cooked] with a turnip.

..מתני׳ ירך שנתבשל בה גיד הנשה אם יש בה בנותן טעם הרי זו אסורה כיצד משערין אותה כבשר בלפת גיד הנשה שנתבשל עם הגידים בזמן שמכירו בנותן טעם ואם לאו כולן אסורין והרוטב בנותן טעם וכן חתיכה של נבלה וכן חתיכה של דג טמא שנתבשלה עם החתיכות בזמן שמכירן בנותן טעם ואם לאו כולן אסורות והרוטב בנותן טעם: גמ׳ אמר שמואל לא שנו אלא שנתבשל בה אבל נצלה בה קולף ואוכל עד שמגיע לגיד איני והאמר רב הונא גדי שצלאו בחלבו אסור לאכול אפילו מראש אזנו שאני חלב דמפעפע ...

Mishnah: A thigh in which the sciatic nerve was cooked, if it has [enough] to give flavor [to the thigh], this [thigh] is forbidden. How do we measure it? Like meat [cooked] with a turnip. A sciatic nerve that was cooked with other nerves, at a time when one [still] recognizes it, [the standard for forbidding] is when it gives flavor. If [it is] not [recognized], all of it is forbidden. And [in] broth, when it gives flavor. And so too with a piece of a nevelah [an improperly slaughtered animal of a permitted species], and so too with a piece of prohibited fish which was cooked with [other] pieces: at a time when one recognized them, [the standard] is when it gives flavor; and if [it is] not [recognized], they are all forbidden. And for the broth [the standard] is when it gives flavor. Gemara: Says Shmuel: This is only taught when it's boiled [with the nerve] in, but if it's roasted [with the nerve] in, peel and eat until you get to the nerve.

discuss If any edible portion of the Korban Pesach is leftover until the morning it must be burned. The following Mishna and Gemara this process and also why it is that the sinews are listed separately? If they are edible, they are "Noser" and if not, why must they be burned.

(י) הָעֲצָמוֹת, וְהַגִּידִין, וְהַנּוֹתָר, יִשָּׂרְפוּ בְשִׁשָּׁה עָשָׂר. חָל שִׁשָּׁה עָשָׂר לִהְיוֹת בְּשַׁבָּת, יִשָּׂרְפוּ בְּשִׁבְעָה עָשָׂר, לְפִי שֶׁאֵינָן דּוֹחִין לֹא אֶת הַשַּׁבָּת וְלֹא אֶת יוֹם טוֹב:

(10) The bones, the nerves, and the notar [all of which are left over from the Pesach sacrifice] must be burned on the sixteenth [of Nissan]; If the sixteenth should come out on Shabbat, they must be burned on the seventeenth, since [the burning of these] does not push off [the prohibitions of] Shabbat nor [those] of the festival.

א"א בשלמא בשר נינהו אמטו להכי בעי שריפה אלא אי אמרת לאו בשר נינהו למה להו שריפה א"ר חסדא לא נצרכא אלא לגיד הנשה ואליבא דרבי יהודה

Granted, if you say they are meat, due to that they require burning; but if you say they are not meat, why do they require burning? One should simply discard them like other waste. Rav Ḥisda said: The mishna’s mention of sinews is necessary only for the sciatic nerve, in accordance with the opinion of Rabbi Yehuda.

א"ר איקא בר חיננא כגון שהוכרו ולבסוף נתערבו
Rav Ika bar Ḥinnana said, in response to this attempted proof: The mishna addresses a case where the two sciatic nerves were known, but in the end became mixed together. In other words, at first it was known which was the forbidden right nerve and which was the permitted left nerve. However, they were then mixed together and can no longer be identified. Therefore, due to the uncertainty, they must both be burned.
רב אשי אמר לא נצרכא אלא לשמנו דגיד הנשה דתניא שמנו מותר וישראל קדושים הם ונוהגין בו איסור

Rav Ashi said: The mishna’s ruling that the sinews must be burned is necessary only with regard to the fat of the sciatic nerve, as it was taught in a baraita: The fat around the sciatic nerve is permitted according to Torah law, but the Jewish people are holy and treat it as forbidden. Since it is permitted according to Torah law, it has the status of meat and may not be simply discarded. However, since the Jewish people treat it as forbidden, they do not eat it even from the Paschal lamb. Therefore, it is left until after the time when the meat may be eaten and burned in accordance with the general halakha of leftover.

Part 3


The RAMBAM rules that a person should roast the complete Korban Pesach, removing it only at the time of eating the Korban Pesach.

(יא) כְּשֶׁאָדָם אוֹכֵל אֶת הַפֶּסַח חוֹתֵךְ הַבָּשָׂר וְאוֹכֵל וְחוֹתֵךְ הָעֲצָמוֹת מִן הַפֶּרֶק וּמְפָרְקָן אִם רָצָה. וּכְשֶׁיַּגִּיעַ לְגִיד הַנָּשֶׁה מוֹצִיאוֹ וּמַנִּיחוֹ עִם שְׁאָר הַגִּידִים וְהָעֲצָמוֹת וְהַקְּרוּמוֹת שֶׁיּוֹצְאִין בִּשְׁעַת אֲכִילָה. שֶׁאֵין מְנַקִּין אוֹתוֹ כִּשְׁאָר הַבָּשָׂר וְאֵין מְחַתְּכִין אוֹתוֹ אֶלָּא צוֹלִין אוֹתוֹ שָׁלֵם. וְאִם חֲתָכוֹ חֲתִיכוֹת חֲתִיכוֹת כָּשֵׁר וְהוּא שֶׁלֹּא יֶחְסַר אֵיבָר. צָרִיךְ אָדָם לְהִשְׁתַּדֵּל שֶׁלֹּא יַשְׁאִיר מִבְּשַׂר הַפֶּסַח עַד בֹּקֶר שֶׁנֶּאֱמַר (שמות יב י) "לֹא תוֹתִירוּ מִמֶּנּוּ עַד בֹּקֶר". וְכֵן בַּשֵּׁנִי שֶׁנֶּאֱמַר (במדבר ט יב) "לֹא יַשְׁאִירוּ מִמֶּנּוּ עַד בֹּקֶר". וְאִם הִשְׁאִיר מִמֶּנּוּ בֵּין בָּרִאשׁוֹן בֵּין בַּשֵּׁנִי עָבַר בְּלֹא תַּעֲשֶׂה. וְאֵינוֹ לוֹקֶה עַל לָאו זֶה שֶׁהֲרֵי נִתָּק לַעֲשֵׂה שֶׁנֶּאֱמַר (שמות יב י) "וְהַנֹּתָר מִמֶּנּוּ בָּאֵשׁ תִּשְׂרֹפוּ":

The Ra"avad takes the RAMBAM to task and is incredulous that the RAMBAM would permit the roasting of the Korban Pesach along with the Gid HaNasheh.

(א) כשאדם אוכל את הפסח וכו' עד העצמות והקרומות. א''א בחיי ראשי אין איסור גדול מזה שיצלה הפסח עם גיד הנשה ועם שמנו ועם תרבא דתותי מתנא ועם קרומות שבראש ואם אזכה ואוכל פסח ויביא לפני כזה הייתי חובטו בקרקע לפניו:

Part 4

The Kesef Mishna's Answer

The Kesef Mishna (R' Yosef Karo) attempts to defend the RAMBAM by asserting that because the Gid Hanasheh does not impart any taste to the cooked food (i.e., the roasted Korban) and in light of the concerns of potentially mistakenly cutting off a limb in the removal process, the RAMBAM permitted roasting the Korban Pesach with the GH.

(א) כשאדם אוכל את הפסח חותך הבשר ואוכל וכו': כתב הראב''ד בחיי ראשי אין איסור גדול מזה וכו'. ומ''ש ותרבא דתותי מתנא, י''ל שלא עלה על דעת שרבינו מתיר לצלותו עם חלב האסור מן התורה אלא גיד הנשה שאין בגידין בנ''ט ושמנו שאין בו איסור אלא שישראל קדושים נהגו בו איסור ובפסח לא נהגו כדי שלא יבא לחתך בו אבר אבל חלב האסור מנקרים אותו ואפילו החוטים והקרומות האסורים משום חלב מסירים אותם אע''פ שאין אסורים אלא מדרבנן כמבואר בפ''ח מהמ''א דייקא נמי דקתני שאין מנקין אותו כשאר הבשר דמשמע שמנקין אותו אלא שאינו כשאר בשר.

Part 5

Other Responses

The Bnei Yissasschar

The Bnei Yissasschar asks that according to the Kesef Mishna's answer, HOW did the RAMBAM know that roasting the Korban with the GH is permitted in the first instance rather than simply post facto? While the Bnei Yssasschar does not delve further into the Nosen Ta'am question, he brings a proof that he feels provides a basis for the RAMBAM's permissive ruling.

The Zera Avraham

The Zera Avrohom (collecting correspondence between R' Avraham Luftbar and R Menachem Ziemba) simply posits that it was certainly the case that in Egypt, the original Korban Pesach was roasted fully, including with the GH. It stands to reason that this command did not change in later years and therefore a person was always permitted (and perhaps required) to continue roasting the Korban Peasch with the GH in future years.

The Minchas Yitzchok

The Minchas Yitzchok, with much adoration for the Bnei Yissachar, asks a compelling question. If at the time of the first Pesach in Egypt one was allowed to roast the Korban Pesach with the GH intact, presumably, this also would include the prohibited fats (Cheilev) and yet we find no one who suggests that because it is not listed as a difference between Pesach Mitzrayim and Pesach Doros that one can roast the Korban Pesach with these fats intact. In afct, the Kesef Mishna states that even according to the RAMBAM the Cheilev must be removed prior to roasting the Korban Pesach.

Rather, he says, the RAMBAM can be best understood by the fact that the Halcha states that in order to remove the full GH one must break the edges of the bone. This itself is a prohibited act, specific to the Korban Pesach. Therefore, he says, the RAMBAM understood that it better to roast the Korban Pesach with the GH rather than to break a bone. Rather he suggests, once roasted it will be easier to remove the GH when eating the Korban in a way that will not require you to break a bone.

The Sefas Emes

The Sefas Emes finds support for the RAMBAM from the Gemara we cited to above in Pesachim 83b.

The Chikrei Halachos

The Chikrei Halachos looks to answer the RAMBAM from the Gemara we cited earlier in Chullin 96b that according to the Rambam, roasting meat with a Gid in it does not allow the flavor to spread into the meat itself. The Mishnas Efrayim, on Hilchos Korban Pesach, quotes the Shoel UmEishiv Vol. 4b Siman 204 who independently resolves the Rambam in similar fashion.

The Shaarei Yitzchok

The Shaarei Yitzchok posits that what is really driving the RAMBAM's ruling is the notion that the Korban Pesach cannot be missing any limbs (Mechusar Eiver) when it is being roasted. Further, he says that the GH is considered an Eiver for these purposes. How exactly the GH differs from other forbidden fats which everyone agrees must be removed is not fully answered.

Nonetheless, the distinction he makes is as follows: according to the RAMBAM, there is a separate Mitzvah for the Korban Pesach to be fully roasted (i.e., not missing any limbs). This would include all limbs, even those otherwise prohibited from eating. The Ra'avad, on the other hand, he suggests, views the whole goal of roasting the Korban as being able fulfill the Mitzvah of eating the Korban. Hence, you need only roast those parts that you are allowed to consume--exempting the GH and other prohibited pieces.

The Mishnas Yaavetz

The Mishnas Yaavetz (R' Zolty) posits a similar idea in that the the roasting of the Korban Pesach, according to the RAMBAM, is not simply about how one must eat the Korban. Rather, it is a separate characteristic of the Korban Pesach itself. In other words the Korban Pesach has to be prepared in a certain way and one of the inputs is that it be wholly roasted. What that means for the person eating the Korban is a separate matter and even according to the RAMBAM he agrees you must excise those forbidedn portions. The Ra'avad disagrees and views the roasting as part of Mitzvah of eating the Korban and therefore, there is no need to roast those parts of the animal that are otherwise forbidden.

R' Zolty brings a proof from the Mishna in Zevachim 5:8 that describes the rules governing the Korban Pesach. The Mishnah includes that it must be roasted but does not include eating the Korban Pesach together with Matzoh and Marror. Therefore, he suggests, if the roasting is simply part of the way to eat the Korban than the Mishna should have included the Matzoh and Marror as part of the process. Their absence suggests that roasting the Korban arises from a different perspective--i.e., it is a regulation regarding the Korban itself and not how it is to be eaten.