2,787. What Is a Gift?
Hilchos Nedarim 7:15
Context: Person A is prohibited to benefit from person B; person C is a third party.
If person B gives person C the gift of a feast, saying that person A should be invited, it is prohibited. Even if B gave it to C as a gift without saying anything and only later asked if they should invite person A, it is still prohibited if it appears that person B’s intention in giving the gift was to invite person A. An example of this is if it’s a large feast and person B wants to invite his father, his teacher, etc. The size of the feast shows us that his intention wasn’t really as a gift for person C. The same is true in all comparable cases.
Hilchos Nedarim 7:16
Any gift that, if sanctified by the recipient, is not effectively sanctified, isn’t really a gift. If one person gives another a gift on the condition that he give it to a third person, that third person acquires it when the first recipient gives it to him. If the first recipient doesn’t give it to him, then neither of them acquires it.