דבר שלא בא לעולם חלק ב - הסוגייא בגמרא

MISHNA: If someone is mikadesh a woman, and then says, "I thought she was a Kohenet," but she was a Levite, "Levite," but she was a Kohenet, "Rich," but she was poor - she is mekudeshet because she didnt deceive him.

If he says to a woman, "Behold you are mekudeshet to me, after I convert or after you convert / after I am freed or after you are freed / after your husband dies or after your sister dies / after your yavam performs chalitza." - she is not mekudeshet. Similarly, if one says to his friend, "If your wife gives birth to a girl, she is mekudeshet to me." - she is not mekudeshet. (If the wife of the friend was pregnant, and the fetus was recognizable, his words are good, and if she gives birth to a girl, she is mekudeshet.)

Abaye says: Rabbi Eliezer ben Ya’akov, Rabbi, and Rabbi Meir all think : A person can sell something that does not exist. . . Rabbi Meir, as it is taught : If he says to a woman, "Behold you are mekudeshet to me, after I convert or after you convert / after I am freed or after you are freed / after your husband dies or after your sister dies / after your yavam performs chalitza." - she is not mekudeshet. Rabbi Meir says she is mekudeshet. Rabbi Yochanan The Cobbler says she isn't mekudeshet. Rabbi Yehuda the Prince says she is mekudeshet, and the reason they say she is not mekudeshet is because of discord. [something about saying she is mekudeshet will cause strife of some sort. - JF]

"She is not mekudeshet" - Because they are things that do not yet exist, and now he is incapable of making her mekudeshet.

The Sages taught: "If you consecrate them when they are empty and they were later filled, it is considered a desecration to use them, but it is not considered a desecration to use what is in them. Rabbi Elazar, son of Rabbi Shimon says, 'It is also a desecration to use what is in them.'" . . . Perhaps they're argument is based on the argument of Rabbi Meir and the Rabbis. The first Tanna agrees with the Rabbis that said that a person can not sell something that does not yet exist in the world, while Rabbi Elazar the son of Rabbi Shimon agrees with Rabbi Meir that a person can sell something that does not yet exist in the world. However, you can say that what we learned from Rabi Meir is with regards to something like dates that will certainly come, but in in this case, who can tell you that they will come?

MISHNA: . . . A person says, "Should my wife give birth to a boy, he will receive 100," and she gives birth to a boy - he receives 100. "A girl 200," and she gives birth to a girl, she receives 200. . .

141b

I don't know who taught our Mishna. If you say it's Rabbi Meir, who said that a person can sell something that does not yet exist, perhaps this teaching of Rabbi Meir's is for selling something to someone who exists in the world, but did anyone teach that you can sell something to someone that does not yet exist in the world?

It is taught [in a Mishna] over there. "If you lend someone money with a written document, they can collect only from mishuabdim, but if it is with witnesses, they can even collect from free property."

Shmuel asked, "[If you wrote, 'From property that] I will acquire,' and you acquired [more property], what is it?"

According to Rabbi Meir that said that a person can sell something that doesn't yet exist, there's no need to ask - he certainly acquired it. Rather, ask according to the Rabbis that said that a person can not sell something that does not yet exist.