Suggestion: R. Akiva holds that a Hekesh overrides a Gezerah Shavah. Chachamim hold oppositely.

Answer: No, all agree that a Hekesh is stronger. Chachamim say that the former Parshah teaches to the latter.

Gitin 41b (Beraisa - Rebbi): If one freed half of his slave, the slave becomes half-free;

Chachamim say, he remains a full slave.

(Rabah): They argue about a Get of (half) freedom. Rebbi learns from a Hekesh equating a Get of freedom to redemption money, which can make partial freedom. Chachamim learn from a Gezeirah Shavah from divorce. Just like a woman cannot be half-divorced, a slave cannot be half-freed.

Suggestion: Rebbi and Chachamim argue about whether it is better to learn from a Hekesh or a Gezeirah Shavah.

Rejection: No. All agree that usually, a Gezeirah Shavah is better. Here, money cannot divorce, so we do not learn from divorce that a Get of freedom cannot work half-way.

Pesachim 4b - Question: All agree that Chametz is forbidden after six hours on Erev Pesach. What is the source of this?

Answer (Abaye) Contradiction: It says "Shiv'as Yomim Se'or Lo Yimatzei b'Vateichem" and it says "Ach ba'Yom ha'Rishon Tashbisu Se'or mi'Bateichem"

Resolution: We must say that "Ach ba'Yom ha'Rishon" refers to the 14th (part of it is forbidden).

We do not need "Ach ba'Yom ha'Rishon" to obligate Bi'ur (destroying Chametz) on the night of the 15th and forbid the nights. Bi'ur Se'or is equated to eating Chametz - "Shiv'as Yomim Se'or Lo Yimatzei b'Vateichem Ki Kol Ochel Machmetzes v'Nichresah", and eating Chametz is equated to eating Matzah ("Kol Machmetzes Lo Sochelu b'Chol Moshvoseichem Tochlu Matzos"), which applies at night.

Bava Kama 29b (R. Elazar): One does not own Chametz from noon of Erev Pesach and onwards, but the Torah obligates him for it as if he owned it.

Rambam (Hilchos Chametz 3:7): After after six hours on Erev Pesach one cannot be Mevatel Chametz, for it is not in his Reshus.

Rambam (8): If one was not Mevatel Chametz before six hours, and after six hours he found Chametz that he was thinking about, and it was in his heart but he forgot at the time of Bi'ur and was not Meva'er it, he transgressed Bal Yera'eh and Bal Yimatzei because he did not do Bi'ur or Bitul.

Ra'avad: Perhaps he holds that he transgresses Bal Yera'eh and Bal Yimatzei from six hours. This is wrong. It says "seven days"!

Magid Mishneh: The Ra'avad should have learned from the Rambam's introduction to Hilchos Chametz, in which he lists the Mitzvos. He explicitly says that Bal Yera'eh and Bal Yimatzei apply seven days. On the 14th is only the Mitzvah of Tashbisu (Bi'ur). Here the Rambam means that since Bitul does not work after six hours, even if he did Bitul then, since he did not do Bi'ur, he transgresses Bal Yera'eh and Bal Yimatzei when Pesach comes.

Noda bi'Yehudah (1 OC 20): Many Rishonim say that one does not transgress Bal Yera'eh and Bal Yimatzei until night. Almost all Acharonim say that this is obvious. I disagree with them, and with the Magid Mishneh. If the Rambam holds that one does not transgress Bal Yera'eh and Bal Yimatzei until night, why did he mention that he found the Chametz after six hours? He already said that Bitul does not help then! Surely, it was to teach that one transgresses Bal Yera'eh and Bal Yimatzei after six hours! Also, why didn't the Ra'avad express astonishment at the Rambam (like he always does) for ruling unlike the verse without any support? I will explain this, and answer Tosfos' (28b DH Im) question, why R. Shimon needs a verse to teach that the Isur to eat Chametz is only at night.

Noda bi'Yehudah (ibid.): A Gezeirah Shavah "Se'or-Se'or" teaches about accepting deposits from Nochrim (Pesachim 5b). The Gezeirah Shavah also applies to the verse "Ach ba'Yom ha'Rishon Tashbisu Se'or." If not, what is the source to permit accepting a deposit without Acharayos? He should transgress Tashbisu! Rather, we learn Tashbisu from Bal Yera'eh and Bal Yimatzei. We say that Bal Yera'eh is Nitak to (fixed through) the Aseh of Tashbisu (Pesachim 95a). All agree that "ba'Yom ha'Rishon Tashbisu" refers to Erev Pesach! We must say that the Gezeirah Shavah teaches that it applies also during Pesach. (Hagahah - the end of the verse "Ad Yom ha'Shvi'i" obligates the entire Pesach! Indeed, the Rambam holds that Tashbisu is only on Erev Pesach, and he holds that Bal Yera'eh is not Nitak l'Aseh.) We learn the Gezeirah Shavah also in the other direction, that Bal Yera'eh and Bal Yimatzei apply after six hours, just like Tashbisu. (Hagahah - a Hekesh is stronger than a Gezeirah Shavah! We must say that the Hekesh is only to eating Chametz when the punishment is Kares, i.e. during Pesach, but not on Erev Pesach.) However, Tosfos (Zevachim 48a DH d'Kulei) concluded that a Hekesh is always stronger than a Gezeirah Shavah. However, here it is not clear that the Isur to eat Chametz begins only at night, therefore we can fulfill both the Gezeirah Shavah (to teach that Bal Yera'eh and Bal Yimatzei apply from six hours) and the Hekesh (to teach that the Lav to eat Chametz is from six hours). R. Shimon needs a verse to teach that the Isur to eat Matzah is only at night, for if not he would learn from Bal Yera'eh that it is from six hours. R. Yehudah holds that the Isur to eat Chametz is from six hours. If so, the Gezeirah Shavah teaches that also Bal Yera'eh is from six hours, for it does not contradict the Hekesh to eating Chametz. The Rambam holds that even though the Halachah follows R. Shimon (who permits Chametz that a Yisrael owned during Pesach) after Pesach, regarding Erev Pesach, the Halachah follows R. Yehudah against R. Shimon (this is the general rule). The Ra'avad holds that just like the Halachah follows R. Shimon after Pesach, it follows him on Erev Pesach. There is no Diyuk from the Rambam's list of Mitzvos, for he does not list Mitzvos derived through Drashos, only what is explicit in the Torah.

Note: The first Mitzvah he lists is the Isur to eat Chametz from after six hours on Erev Pesach, which is learned from a Drashah!

Rashi (Nedarim 86b DH Chametz): If Reuven borrowed from a Nochri and made his Chametz an Apotiki (collateral from which the loan will be collected) and six hours on Erev Pesach came, Reuven transgresses Bal Yera'eh and Bal Yimatzei. The Isur Chametz uproots the Nochri's lien. Reuven must do Bi'ur.

Rashi (Bava Kama 29b DH mi'Shesh): The Torah considers it as if Chametz is in one's Reshus to transgress Bal Yera'eh and Bal Yimatzei.

Tosfos (Zevachim 48a DH d'Kulei): Here we say that all agree that a Hekesh is stronger than a Gezeirah Shavah. In Gitin, we say oppositely! Here we mean that it is better to learn the Gezeirah Shavah only partially, than to totally nullify the Hekesh. There, in any case the Hekesh teaches other matters. Also, there we know that a Get can free a slave only from the Gezeirah Shavah to divorce, so it is better to learn from a Gezeirah Shavah to divorce, than from a Hekesh to freedom through money.

Shulchan Aruch (OC 443:1): Chametz is Asur b'Hana'ah from after six hours on Erev Pesach.

Magen Avraham (1): The Isur is mid'Oraisa. This refers to Tashbisu. He does not transgress Bal Yera'eh and Bal Yimatzei until night.

Sha'agas Aryeh (84): Since we learn Tashbisu from a Gezeirah Shavah "Se'or-Se'or" from Bal Yera'eh and Bal Yimatzei, we should also learn in the other direction to obligate Bal Yera'eh and Bal Yimatzei from after six hours on Erev Pesach! We do not, for Hashbasas Se'or (i.e. Bal Yimatzei) is Hukash to eating Chametz, and eating Chametz is Hukash to eating Matzah, which is at night. A Hekesh is stronger than a Gezeirah Shavah (Gitin 41a, Zevachim 48a). Even according to the opinion that a Gezeirah Shavah is stronger, here the Torah revealed "seven days", but not after after six hours on Erev Pesach.

Note: What is his source from Gitin 41a that a Hekesh is stronger? Chachamim surely disagree, and perhaps also Rebbi! Also, perhaps all agree that a Gezeirah Shavah is stronger than learning a Hekesh from a Hekesh. In Kodshim, we learn from a Gezeirah Shavah, but not from Hekesh mi'Hekesh!

Sha'arei Teshuvah (440:1): If one accepted a deposit of Chametz from a Nochri with Acharayos (liability to pay if it will be lost), if he did not designate a separate place for it or make a wall to separate it from his Reshus, it is forbidden after Pesach. If he designated a place or made a wall after six hours, even though he transgressed Tashbisu, it is permitted after Pesach, for removing from one's Reshus exempts from Bal Yera'eh and Bal Yimatzei even during Pesach.

Shirei Korban (on Yerushalmi Pesachim 36b): The Yerushalmi brings a teaching that says that Bal Yera'eh does not apply on Erev Pesach, and says 'this is like R. Meir, who holds that the Isur on Erev Pesach is mid'Rabanan.' Since the Bavli holds that all agree that the Isur on Erev Pesach is mid'Oraisa, it holds that Bal Yera'eh applies on Erev Pesach!

Rebuttal (Tosfos ha'Rid on Yerushalmi 4a, Shevet ha'Levi 8:110:3): The Yerushalmi says that these depend on the other, for it holds that the Hekesh applies to the entire Isur of eating Chametz. Tosfos (Pesachim 5a DH d'Ha) explains that the Bavli makes the Hekesh only regarding the Isur of Chametz punishable by Kares, i.e. during the seven days.

Shevet ha'Levi (ibid.): To resolve the Sugyos, Tzafnas Pane'ach says that one who transgressed Bal Yera'eh during Pesach retroactively transgresses from Erev Pesach after six hours. This requires great investigation.

Chak Yakov (1): Also Teshuvas Maharam (me'Rotenburg 162) says that Bal Yera'eh does not apply until night. However, Rashi holds that it applies on Erev Pesach after six hours.

Sha'ar ha'Tziyon (2): Also R. Chananel (Pesachim Sof 6b) holds that it applies on Erev Pesach after six hours, and Ba'al ha'Itur says so according to R. Yehudah.

Mishnah Berurah (1): Several Poskim agree that Bal Yera'eh and Bal Yimatzei do not apply until night, since it says "seven days." In any case, every moment he has Chametz in his house he transgresses the Aseh of Tashbisu, which is from six hours.

Bi'ur Halachah (DH Asruhu): B'Di'eved, if one sold Chametz to a Nochri in the sixth hour, Mishbetzos Zahav (448:6) says that in any case after Pesach it is not considered Chametz that one owned during Pesach. Some say so even if he sold it after six hours, since some Poskim say that Bal Yera'eh and Bal Yimatzei do not apply until night. See Noda bi'Yehudah (2 OC 63, who says that even though we follow R. Yehudah regarding Erev Pesach, regarding after Pesach we follow R. Shimon, who says that one did not transgress Bal Yera'eh and Bal Yimatzei on Erev Pesach).

Kaf ha'Chayim (1): Rashi holds that Bal Yera'eh applies on Erev Pesach, but we rule that it does not.