THE CASE OF 'AFTER YOU'
(Beraisa - Rebbi): If one said 'my property is (given) to you (Shimon), and after you (die) to Ploni', and Shimon sold the property and spent the money from the sale, after Shimon dies, Ploni takes the property from the buyer. (Even in a case of 'after you', Shimon owns the Peros, but not the property, therefore his sale is void);
R. Shimon ben Gamliel says, Ploni receives only what Shimon leaves over (in this case, nothing. This is because Shimon owned the property.)
Contradiction (Beraisa - Rebbi): If one said 'my property is to you (Shimon), and after you to Ploni, Shimon may (l'Chatchilah) sell the property and spend the money;
R. Shimon ben Gamliel says, Shimon is entitled only to eat the Peros.
Both Tana'im contradict themselves!
Answer - part 1 (for Rebbi): In Beraisa #1, Rebbi teaches that Shimon cannot sell the (permanent rights to the) property. In Beraisa #2, he teaches that he may sell the Peros (for the rest of his life).
Answer - part 2 (for R. Shimon ben Gamliel): In Beraisa #1, R. Shimon teaches that (b'Diavad) if Shimon sold the property, the sale stands. In Beraisa #2, he teaches that he should not sell the property (because the giver wanted Ploni to receive it after Shimon).
(Abaye): A crafty Rasha is one who counsels Shimon (in the above case) to sell the property, according to R. Shimon ben Gamliel.
(R. Yochanan): The Halachah follows R. Shimon ben Gamliel;
R. Shimon admits that if Shimon gave the property for a Matnas (gift of a) Shechiv Mera, this gift is void. Ploni gets it after Shimon dies.
Question: What is the reason?
Answer (Abaye): A Matnas Shechiv Mera only acquires after death. Ploni already acquired the moment Shimon died.
Question: Abaye said differently!
Question: When does a Matnas Shechiv Mera take effect?
Answer #1 (Abaye): It takes effect at the moment of death.
Answer #2 (Rava): It takes effect after death.
Answer: Abaye retracted from this (Answer i:2).
Suggestion: Perhaps Abaye retracted from the above teaching (Answer h:3)!
Rejection: (Presumably, one does not give his property until after his death, just like (if he did not specify otherwise, we assume that) a man does not decide absolutely to divorce until after death.)
(Mishnah): If one said 'this is your Get if I die (from this illness)', 'this is your Get from this illness', or 'this is your Get after I die', the Get is void.
(R. Zeira): The Halachah follows R. Shimon ben Gamliel, even if he received slaves and freed them (they are free).
Question: This is obvious!
Answer: One might have thought that the giver did not give in order that Shimon will transgress with the gift (i.e. free them), and this invalidates the gift. R. Zeira teaches that this is not so.
(Rav Yosef): The Halachah follows R. Shimon ben Gamliel, even if he made the gift shrouds for a dead person.
Question: This is obvious!
Answer: One might have thought that the giver did not give in order that Shimon will make it forbidden to benefit from it. Rav Yosef teaches that this is not so.
GIVING AN ESROG
(Rav Nachman bar Rav Chisda): If Reuven told Shimon 'I give to you this Esrog for a gift, and after you to Ploni', and Shimon took it to fulfill the Mitzvah, Rebbi and R. Shimon ben Gamliel argue about whether or not he was Yotzei..
Objection (Rav Nachman bar Yitzchak): The Tana'im argue only about whether or not Kinyan Peros is k'Kinyan ha'Guf;
Here, all agree that (Reuven gives it in a way that) Shimon is Yotzei. If not, what was the point of the gift?!
(Rav Nachman bar Yitzchak): Rather, all agree that Shimon was Yotzei. They argue about when he sold it (Rebbi invalidates the sale, and R. Shimon upholds it) or ate it (Rebbi says that he must pay Ploni its value, and R. Shimon exempts him).
(Rabah bar Rav Huna): If orphans bought an Esrog with money of the estate, and one of them took it to be Yotzei (fulfill the Mitzvah), he was Yotzei only if the others would allow him to eat it (this shows that he owns it).
This is only if there is an Esrog for each brother. If there are (only) other fruits for the others, he was not Yotzei (they do not consent that he should own it).
(Rava): If one said 'take this Esrog on condition that you return it to me', and the recipient took it for the Mitzvah, he was Yotzei only if he returned it afterwards.
Rava teaches that a gift on condition to return it is a valid gift.
A GIFT ON CONDITION TO GET IT BACK
Leah owned a date tree in Rav Bivi bar Abaye's property. Whenever she would go to take the fruit, he was upset. She transferred ownership to him for the rest of his life. He gave it to his son.
(Rav Huna brei d'Rav Yehoshua): He cannot do that! Even R. Shimon ben Gamliel said that a gift to someone else takes effect only when the giver said 'after you to Ploni' (because the giver gave away the Peros and the permanent rights to the property);
Here, she stands to get back the tree after Rav Bivi dies. All agree that he cannot give it away!
(Rava citing Rav Nachman): If one said 'I give to you this ox for a gift on condition that you return it to me', if Shimon was Makdish it and returned it, it is Hekdesh, and he fulfilled the stipulation.
Question (Rava): Why is it considered that he returned it? (The giver wanted to get it back to use it!)
Answer (Rav Nachman): Nothing is missing (he returned the ox intact, even though the owner may not use it).
(Rav Ashi): If he said 'on condition that you return it', this was fulfilled;
If he said 'on condition that you return it to me', he stipulated that he will be able to use it.
ONE WHO REFUSES TO RECEIVE A GIFT
(Rav Yehudah): If Reuven wrote his property to Levi, and Levi said 'I do not want it', he acquires it anyway, even if he screams in protest;
(R. Yochanan): He does not acquire it.