Gemara

22b (Mishnah - R. Meir): A Kena'ani slave acquires his freedom through money given by others;

Chachamim say, he acquires his freedom through money he gives himself (but it must be of others).

23b (Rabah): This is when someone told the slave 'acquire this money on condition that your master has no rights to it';

R. Meir holds that once he says 'acquire', the slave acquires and it belongs to the master. The Tanai ('on condition...') has no effect;

Chachamim say, his Tanai takes effect.

Objection (R. Elazar): If that case, all agree that the slave acquires and it belongs to the master! Rather, they argue when he said 'acquire this money on condition that you will be redeemed through it';

R. Meir holds that once he says 'acquire', the slave acquires and it belongs to the master. The Tanai has no effect;

Chachamim say, the giver limited the acquisition. The slave acquires the money only for redemption (the master gets it only when he frees the slave).

Nedarim 48a (Mishnah): A case occurred in Beis Choron in which a vow forbade Shimon to benefit from his son Levi. Levi was marrying off his son; he told Yehudah 'I give you the courtyard and the banquet just so my father can come and eat.' Yehudah said 'if they are mine, I make them Hekdesh!' Levi said that he did not give to you in order that Yehudah will be Makdish them.

Chachamim: Any gift like this, in which the recipient cannot be Makdish it (Tosfos - because the giver stipulated exactly what must be done with it) is not a gift.

Version #1 (Rava): This is when he said 'they are yours only in order that father will come.' If he said 'they are yours, so father will come', he means 'if you want.' (This is permitted, for the gift was unconditional.)

Version #2 (Rava): Do not think that we forbid only when he said 'they are not yours (except for father to come).' Rather, even if he said 'they are yours so father will come' it is forbidden, because the banquet proves what his intention is. (It was not an unconditional gift.)

48b: Shimon forbade his property to his son. Friends suggested that perhaps a son of his son will be a Chacham! Shimon said 'my son should acquire the property on condition to give it to his son if his son will be a Chacham.'

(Rav Nachman): This works. One who does Chalipin (a Kinyan made through giving a garment) takes the garment only in order to give something else!

Question (Rava, against Rav Nachman): The gift of Beis Choron was a Kinyan on condition to give to someone else, and it did not work!

Answer #1 (Rav Nachman): There, the banquet proved that the gift was insincere.

Question (Mishnah - Chachamim): Any gift that the recipient cannot make Hekdesh is not a gift.

Suggestion: 'Any' includes this case (the gift for the sake of the grandson. The Kinyan is invalid!)

Answer: No, it includes Version #2 of Rava's (48a. Even if he had said 'they are yours in order that father will come', this is forbidden.)

88a (Mishnah): If Shimon vowed not to benefit his son-in-law, he can give money to his daughter and say 'this is a gift, on condition that your husband has no authority over it. It is only for you to buy food with it and to eat the food.'

(Rav): This works only if he says 'it is only for you to buy food with it and to eat it.' If he says 'do like you want with it', her husband acquires the money.

Bava Basra 134b (Beraisa): A case occurred in which Reuven's sons were acting improperly. He wrote his property to Yonason ben Uzi'el. Yonason sold a third of it, made a third Hekdesh, and returned a third to Reuven's sons. Shamai thought that the return of the property was invalid, because Reuven was adamant that his sons not get it.

Yonason: You have no more ability to undo this than the sale and Hekdesh. If you cannot undo them, the return also stands.

Shamai: You refuted me.

Shamai originally thought that this is like the gift of Beis Choron.

137b (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.

Rishonim

The Rif and Rosh (Nedarim 5:4) bring Version #2 of Rava.

Rambam (Hilchos Nedarim 7:15): If Shimon gave a gift to Levi, and said 'this feast is a gift to you. Ploni, who is Mudar Hana'ah from me, will come and eat with us', it is forbidden. Even if he gave Stam, and then said 'do you want Ploni to come and eat with us?', if the end reveals that from the beginning he intended only in order that Ploni eat, it is forbidden. E.g. it was a big feast, and his father or Rebbi was Mudar, and he wanted him to eat. The meal proves that he did not intend to transfer ownership. The same applies to all similar cases.

Rosh (Bava Basra 8:38): The Mishnah invalidates a gift if the recipient cannot make it Hekdesh. He must also be able to sell it or give it for a gift. If this were not true, how did Shamai try to show from Matanas Beis Choron (which depends only on ability to be Makdish) that Yonason cannot give to the children?! This is when the giver did not specify. If he specified, even if he stipulated not to give, sell or make it Hekdesh, or not to do anything other than the giver's intent, it is valid. We learn from the case in Nedarim, in which Shimon said 'my son should acquire the property on condition to give it to his son if his son will be a Chacham.' Rav Nachman said that this works. Rava asked from the gift of Beis Choron. Rav Nachman said that there, the banquet proves that the gift was insincere. The Yerushalmi explains the Mishnah to mean that if a gift is like that in Beis Choron, i.e. a mere scheme in which the recipient cannot make it Hekdesh, it is not a gift.

Nimukei Yosef (Bava Basra 61a DH Garsinan): Shamai rebuked Yonason for transgressing the will of the deceased. There is an Umdena (clear estimation) that Reuven gave in order that his sons will not benefit from the property, even though he did not specify. Shamai thought that it is as if the gift was on condition that Yonason not return to his sons. Shamai erred. Since he gave Stam, he intended for whatever Yonason will do with it. Yonason replied that just like you cannot undo the sale and Hekdesh, since the gift was for his benefit, you cannot undo what I returned to his sons. Elsewhere, we follow Umdena even if one did not specify, e.g. one who heard that his son died and wrote all his property to someone else. There, there was no reason for him to specify, for he thought that his son was dead. Here, if he wanted the gift to be conditional, he should have specified, especially because a Chacham (Yonason) is apt to have mercy on the giver's sons, and they did not sin against Yonason. Even had Yonason returned everything to the sons, Reuven could not retract. However, R. Shimshon explains that Reuven could not retract only because Yonason already benefited from the gift. Since he benefited from part, the entire gift was valid, for it cannot be half-valid. Some Meforshim say that the case was like the gift of Beis Choron; Reuven had vowed that his sons not benefit from his property, and now regretted it. He wanted that Yonason will return it to his sons. Yonason sold and was Makdish part to show that it was a total gift, so there was no Isur to give part to the sons.

Ran (Nedarim 48a DH Lishna): Normally, 'he will come (and eat)' is not a Tanai. Here is different, for we can testify that one does not prepare a feast for his son's wedding and give it to someone else. This shows that 'he will come' was a absolute Tanai. However, the Rashba says that this is only if he said so at the time of the gift, but not if he said so afterwards. The Rambam holds that even if he said so afterwards, it is not a gift.

Poskim

Shulchan Aruch (CM 241:5): Some say that a gift is invalid unless Shimon gave with intent that Levi may do whatever he wants with it. This is when Shimon gave it Stam, but it is clear that he does not want Levi to do whatever he wants with it. If he stipulated that Levi cannot give it to another or sell it or be Makdish it, or even if he said that he can use it only for a certain matter, it is a gift only for that matter.

Source (Gra 19): We find that one can give to a slave on condition that (his master gets no rights in it, rather,) the gift will be used to redeem him (Kidushin 23b). One can give to his daughter on condition that her husband has no authority over it (Nedarim 88a).

Prishah (8 DH Aval): Saying that Levi cannot do certain things is like stipulating that he makes Levi a partner. Shimon reserved the right that Levi cannot be Makdish it. Monetary stipulations are valid.