Nedarim 93
אמר רבא ת"ש האומר לבנו קונם שאי אתה נהנה לי ומת יירשנו בחייו ובמותו ומת לא יירשנו ש"מ אדם אוסר דבר שברשותו לכשיצא מרשותו שמע מינה:
propounded: What [if one says to his neighbour.] 'Konam, if you enter this house,' and then he sells it or dies: Can one prohibit that which he owns [for the prohibition] to be effective even when it leaves his ownership, or not? — Said Raba, Come and hear: If one says to his son, 'Konam that you benefit not from me,' and he dies, he is his heir. [But if he explicitly stipulates] during his lifetime and he dies, he does not succeed him. This proves that one can prohibit that which he owns [for the prohibition] to hold good when it leaves his ownership. The proof is conclusive.
תנן התם קונם פירות האלו עלי קונם הן על פי קונם הן לפי אסור בחילופיהן ובגידוליהן
We learnt elsewhere: [If one says.] 'Konam be these fruits to me,' or, 'Be they konam for my mouth,' or, 'Be they konam to my mouth': he is forbidden [to benefit] from what has been exchanged for them or grown from them.<span class="x" onmousemove="('comment',' Infra 57a. ');"><sup>2</sup></span>
בעי רמי בר חמא אמר קונם פירות האלו על פלוני מהו בחילופיהן מי אמרינן גבי דיליה הואיל ואדם אוסר פירות חבירו על עצמו אדם אוסר דבר שלא בא לעולם על עצמו גבי חבירו הואיל ואין אדם אוסר פירות חבירו על חבירו אין אדם אוסר דבר שלא בא לעולם על חבירו
Rami b. Hama propounded. If he vows, 'Konam be these fruits to So-and-so', what of their exchange? Do we say, With respect to oneself, since he can forbid to himself [even] his neighbour's property, he can [likewise] forbid to himself what is not yet in existence;<span class="x" onmousemove="('comment',' What may be given for the produce subsequent to the vow is regarded as non-existent when the vow is made. ');"><sup>3</sup></span> but as for his neighbour, since one cannot prohibit another's produce to his neighbour, he likewise cannot prohibit what is non-existent;