SITUATIONS WHEN WE DO NOT RELY ON HO'IL
Question (Mishnah): Lechem ha'Panim is never eaten before the ninth day [from when it was baked], and never later than the 11th:
Normally [Erev Shabbos is not Yom Tov], it is baked on Erev Shabbos and eaten on the following Shabbos, the ninth day;
If Erev Shabbos is Yom Tov, they are baked the previous day and eaten on the 10th day;
If Rosh Hashanah falls on Thursday and Friday, they are baked Erev Rosh Hashanah and eaten on the 11th day (see note 28 in Appendix).
This is because [baking] Lechem ha'Panim does not override Shabbos or Yom Tov.
If [mid'Oraisa] one may cook on Yom Tov for Shabbos, they should be baked on Yom Tov! (Tosfos - Rav Chisda holds that the Torah permits preparing on Yom Tov for any Mitzvah if there will not be time after Yom Tov.)
Answer: [Indeed, it is only Shevus (an Isur mid'Rabanan) to cook on Yom Tov for Shabbos -] Chachamim permitted a near Shevus [for Shabbos that is right after Yom Tov, through Eruv Tavshilim], they did not permit a far Shevus [for the following Shabbos].
Question: According to R. Shimon ben Gamliel, who says that the baking overrides Yom Tov but not Yom Kipur, how can we answer?
Answer: The first Tana permits only a near Shevus; R. Shimon permits even a far Shevus.
Question (Rav Mari - Mishnah): Shtei ha'Lechem are eaten on Shavu'os - this is never before the second day [from baking], and never later than the third:
Normally, they are baked on Erev Shavu'os and eaten on Yom Tov, the second day;
If Erev Shavu'os is Shabbos, they are baked Erev Shabbos and eaten on Yom Tov, the third day.
This is because the baking does not override Shabbos or Yom Tov.
If [mid'Oraisa] one may cook on Yom Tov for Shabbos, all the more so one may cook on Yom Tov for Yom Tov itself (Tosfos - Rav Chisda should permit, even though Shtei ha'Lechem are baked primarily for the Korban, not for the sake of Simchas Yom Tov)!
Answer: It says "Lachem" (you may cook for yourselves) - not for Hash-m.
Question: R. Shimon ben Gamliel says that the baking overrides Yom Tov (this shows that "Lachem" does not forbid for Hash-m! Tosfos - Rabah holds like the first Tana, not like R. Shimon.)
Answer: R. Shimon holds like Aba Sha'ul, who expounds "Lachem" - not for Nochrim.
THINGS NOT EXEMPTED BY HO'IL
Question (Rav Chisda): We do not say Ho'il!
(Mishnah): A person can be lashed eight times for plowing one furrow - if he plows with a Hekdesh ox and donkey, where Kil'ayim was planted in a vineyard, in Shemitah, on Yom Tov; he is a Kohen and a Nazir, and he plows over Tum'as Mes.
If we say Ho'il, he should be exempt for plowing on Yom Tov, Ho'il the dirt is fitting to cover the blood of a bird [if he will slaughter one on Yom Tov! See note 29 in Appendix.]
Answer #1 (Rav Papa bar Shmuel): He plowed soft rocks (they may not be used to cover blood).
Question: One could grind them up (then they could be used)!
Answer: It is forbidden to grind them on Yom Tov.
Question: One could grind them up in an unskilled way (this is permitted mid'Oraisa on Yom Tov)!
Answer #2: He plowed in a rocky area.
Question: A rocky area cannot be seeded (why is he liable for Kil'ayim, plowing on Yom Tov and Shemitah?)!
Answer: It is rocky on top and there is loose dirt underneath.
Rejection: If so, the loose dirt could be used to cover (Question a:2 returns)!
Answer #2 (Mar bar Rav Ashi): He plowed in mud (it cannot be used for covering, for it sticks together).
Question: Mud cannot be seeded!
Answer: The ground is wet (it can be seeded, but it does not crush into dirt, so it is invalid for covering).
Question (Abaye - Mishnah): One who cooks Gid ha'Nasheh in milk on Yom Tov and eats it is lashed five times - for cooking a Gid [ha'Nasheh, which may not be eaten] on Yom Tov, for eating a Gid, for cooking meat and milk, for eating meat and milk, and for burning on Yom Tov.
If we say Ho'il, he should be exempt for burning on Yom Tov, Ho'il it is fitting for a need [cooking permitted food]!
Answer #1: The text of the Mishnah is mistaken - it should omit burning on Yom Tov - rather, the Gid was of a Neveilah, he is lashed for eating Neveilah.
Rejection (R. Chiya's Beraisa): He is lashed twice for eating and three times for cooking.
Answer #2: Rather, it should omit burning, and it should say that the wood was Muktzeh.
Question: Is Muktzeh mid'Oraisa?! (Why is he lashed for it?)
Answer (Rabah): Yes! It says "V'Hayah ba'Yom ha'Shishi v'Hechinu Asher Yavi'u" (one must prepare what he will use on Shabbos);
The Lav against using Muktzeh is "Lo Sa'aseh Chol Melachah."