1) GRANTING A GIFT TO ONE WHO IS FIT TO INHERIT
OPINIONS: Rav Acha brei d'Rav Avya says that according to Rebbi Yochanan ben Berokah, when a Shechiv Mera says to a person who is fit to inherit him (such as his son), "Nechasai Lecha v'Acharecha l'Ploni" -- "My property shall be to you, and after you it shall be to so-and-so," the property is given to the first person unconditionally. Even when the first person dies, the second person does not receive the property, but rather the heirs of the first person receive it. Since he is fit to inherit the Shechiv Mera, the Shechiv Mera's granting of the property to him is considered an inheritance (Yerushah) and not a gift, and an inheritance has no termination; once a person inherits property, that property is then inherited by his children when he dies and the line of inheritance is not discontinued. The Halachah follows the view of Rebbi Yochanan ben Berokah and Rav Acha brei d'Rav Avya's ruling.
What is the Halachah, though, when a Shechiv Mera specifically says that he wants the first person (who is fit to inherit him) to receive the property as a gift (for example, he says, "Nechasai Lecha b'Matanah...")? Is it then considered a gift, such that when the first person dies the property will be given to the second person in fulfillment of the Shechiv Mera's words, or is it still considered a Yerushah?
(a) The RASHBAM (DH Im Amar l'Echad) says that Rav Acha's ruling applies only when the Shechiv Mera did not specify how he wants the property to be granted to the first person (or, obviously, if he stated explicitly that the property should be given to him as an inheritance). If, however, he explicitly states that he wants the property to be given as a gift, then the first person receives it only as a gift, which is then terminated upon his death and the property is transferred to the second beneficiary as a gift.
(b) The RAMBAN maintains that even when the Shechiv Mera specifies that he wants his property to be given to the first person as a gift, since the first person is fit to inherit him the property is given to him as an inheritance and not as a gift, and thus the second person does not receive it at all.
The RAMBAM (Hilchos Zechiyah 12:4) also rules that "the term 'Matanah,' when used with regard to someone who is fit to inherit the giver, is considered an inheritance," and thus even when the Shechiv Mera says that he is giving his property to the first person (who is fit to inherit him) as a gift, it is considered an inheritance and has no termination. This is also the ruling of the SHULCHAN ARUCH (CM 248:1).
However, the Rambam later (12:6) writes that when the Shechiv Mera explicitly states, "My property shall be given to you as a gift that has a termination and not as an inheritance that has no termination," the property indeed is given as a gift and not as an inheritance.
The Mefarshim dispute what the Rambam means. According to the RIVASH (#160), the Rambam means that the Shechiv Mera must say exactly this formula in order for the property to be given as a gift. According to the MACHANEH EFRAIM (Hilchos Zechiyah #39, and according to the "Chacham" to whom the Rivash is addressing his response), the Rambam maintains that as long as it is clear that the Shechiv Mera has intention to give the property only as a gift, his words are upheld and the property is given only as a gift. This is also the ruling of the S'MA (CM 248:3).
(c) The RA'AVAD and RIVASH (#167; see TESHUVOS HA'RASHBA 3:122) maintain that regardless of the wording that the Shechiv Mera uses, the property is also given to the person who is fit to inherit him as an inheritance and not as a gift.
Why should this be so? If the Shechiv Mera explicitly states, as the Rambam writes, that the property should be given "as a gift that has a termination and not as an inheritance," why is his desire disregarded?
The KOVETZ INYANIM explains that according to these Rishonim, the enactment of the Rabanan that the verbal command of a Shechiv Mera is as binding as a written document applies only when his word does not contravene the law of the Torah. In this case, the Torah says that the one who is fit to inherit the Shechiv Mera shall receive the property as an inheritance, while the Shechiv Mera says that he shall receive the property as a gift. Since the Shechiv Mera's order contradicts the law of the Torah, in such a case the Shechiv Mera's words are disregarded (with regard to giving the property as a gift) and the property is given to the first person (as the Shechiv Mera commanded) as an inheritance (as the Torah requires).
(According to the other Rishonim, such as the Rashbam, the enactment of the Rabanan that a Shechiv Mera's words are binding applies even in such a case. Since the Shechiv Mera is able to give his property as a gift to anyone he chooses, the fact that he chooses to give it as a gift to someone who is fit to inherit him is not considered to be in conflict with the Torah's law.)
2) "TOCH KEDEI DIBUR K'DIBUR DAMI"
OPINIONS: The Gemara mentions that the principle of "Toch Kedei Dibur k'Dibur Dami" applies for all Halachos except for idolatry (Avodah Zarah) and marriage (Kidushin). The Gemara in Nedarim (87a) adds that it does not apply for blasphemy (Megadef) and divorce (Gerushin). (TOSFOS explains that the reason why the Gemara here does not mention Megadef and Gerushin is that Megadef is included in Avodah Zarah, and Gerushin is included in Kidushin, since the reason for why "Toch Kedei Dibur" does not apply to Kidushin is equally valid with regard to Gerushin.)
The Rishonim differ about the source for this principle and about the mechanics of how it works.
(a) The RAN in Nedarim (87a) writes that the principle of "Toch Kedei Dibur" and its exceptions are mid'Oraisa. The Torah assumes that a person is never totally committed to his speech or actions and he always reserves the right to retract within the small amount of time of "Toch Kedei Dibur." However, when he performs actions which are of a very severe nature (the exceptions mentioned in the Gemara), he does not begin the action until he is absolutely committed to doing it, and therefore he does not reserve in his mind the right to retract.
(b) RABEINU TAM maintains that the Halachah of "Toch Kedei Dibur" is a Takanah d'Rabanan. The Rabanan instituted this principle in order to enable a buyer to greet his teacher while in the midst of a purchase in such a way that the greeting does not constitute an interruption between the words he said before and the words he said afterwards. TOSFOS in Nedarim cites this opinion in the name of Rabeinu Eliezer. Tosfos asks, however, that "Toch Kedei Dibur" cannot be a Takanah d'Rabanan because it applies even with regard to Halachos that are mid'Oraisa.
(c) The RASHBAM here writes that the principle of "Toch Kedei Dibur" is mid'Oraisa in all cases, including the exceptions mentioned in the Gemara. Mid'Oraisa, one may retract within "Toch Kedei Dibur" even in cases of Megadef, Avodah Zarah, marriage, and divorce. However, the Rabanan enacted that "Toch Kedei Dibur" does not work in those cases. They enacted that it does not work in cases of Megadef and Avodah Zarah because of the severity of the act. They enacted that it does not work in cases of marriage and divorce in order to prevent rumors from spreading which would ruin the reputation of the children born from the union.
The Rishonim question the opinions of the Ran and Rabeinu Tam based on the cases discussed by the Gemara in Nedarim. The Gemara says that if one tore Keri'ah for a relative before the relative died, and then the relative died within "Toch Kedei Dibur" of the Keri'ah, the mourner need not tear again. The reasoning of the Ran certainly does not apply, for the person who tore Keri'ah was not transacting any sort of deal from which he might wish to retract. Rather, at the time he tore Keri'ah, he was not yet obligated to tear because the relative had not yet died, and thus his Keri'ah should be ineffective. The same is true in the case that the Gemara mentions in which a man annulled a Neder mistakenly thinking that it was his wife who made the Neder, and "Toch Kedei Dibur" he discovered that it was actually his daughter who made the Neder. The Gemara applies the principle of "Toch Kedei Dibur" even though there is no question of indecision, but merely a lack of knowledge which was rectified only after the act.
According to Rabeinu Tam, who explains that the principle of "Toch Kedei Dibur" is a Takanah d'Rabanan enacted for one who needs to greet his teacher while he is in the middle of a transaction, the case of Keri'ah is similarly problematic since there is no reason to apply the principle of "Toch Kedei Dibur" there.
1. TOSFOS in Bava Kama (73b) answers that even though Rabeinu Tam's reasoning for "Toch Kedei Dibur" does not apply to Keri'ah, nevertheless the Rabanan instituted the leniency of "Toch Kedei Dibur" as a special leniency in the Halachah of Keri'ah.
TOSFOS here in Bava Basra (DH v'Hilchesa) answers that "Toch Kedei Dibur" applies to Keri'ah because the Rabanan instituted a "Lo Plug" -- since in some situations the rule applies, they enacted that it apply in all situations.
2. These answers do not resolve the questions on the Ran's opinion from the Halachos of Keri'ah and Hafaras Nedarim. It must be that, according to the Ran, the basic principle of "Toch Kedei Dibur k'Dibur Dami" is a universal rule that states that anything which happens within the time frame of "Toch Kedei Dibur" is non-sequential; it is immaterial what happened first. Therefore, the Keri'ah is considered as though it happened after the death. The Ran said his reasoning only in order to differentiate between normal acts and transactions to which the principle of "Toch Kedei Dibur" applies, and Avodah Zarah (and Megadef), Gitin, and Kidushin -- acts which are final and irrevocable once performed, due to their severity, and are therefore excluded from the rule of "Toch Kedei Dibur k'Dibur Dami."