Question: The Mishnah cannot be R. Akiva. He holds that a person may acquire Davar she'Lo Ba l'Olam (something that is not yet in the world, so she would be Mekudeshes later)!

(Mishnah): If a woman said to her husband 'what I produce is Konam (forbidden like a Korban) to your mouth', he need not annul this vow;

R. Akiva says, he must annul it, lest she produce more than she is obligated. (Even though her productivity is not yet in the world, her vow takes effect!)

Answer (Rav Huna brei d'Rav Yehoshua): The case is, she said 'My hands are sanctified to their Maker'. Her hands are in the world.

This argues with Rav Nachman bar Yitzchak.

(Rav Nachman bar Yitzchak): Each of the following Chachamim learned from his Rebbi that a person can acquire Davar she'Lo Ba l'Olam: Rav Huna from Rav from R Yanai from R. Chiya from Rebbi from R. Meir from R. Eliezer ben Yakov from R. Akiva.

(Rav Huna): If one sold the fruits that a date tree will produce, before they come to the world he can retract the sale. After they come to the world, he may not retract the sale;

(Rav Nachman): Even after they come to the world, he can retract;

Rav Nachman agrees that if the buyer took the fruit, we do not take it from him.

(Rav): If Reuven told Levi 'When I buy this field it should become yours from now', Levi acquires it.

R. Yanai's sharecropper used to bring to him a basket of fruit every Erev Shabbos. Once he delayed coming. R. Yanai took Ma'aser from his own fruits on the fruit he expected to receive.

Support (R. Chiya - Beraisa): "In order that you should learn to fear Hash-m all days" - this refers to Shabbos and Yom Tov.

We do not need a verse to permit taking Ma'aser in order to eat the Chulin. Tithing on Shabbos and Yom Tov is forbidden only mid'Rabanan!

Rather, the verse permits tithing in a case like R. Yanai's, even though it is like a matter that did not come to the world.

R. Yanai: I was shown in a dream "A broken stick". Doesn't this refer to "You have trusted on a support, this broken stick"?!

R. Chiya: No, it is "A broken stick will not break (... he will carry out the law to its truth)".

(Beraisa - Rebbi): "Do not secure a slave to his master" refers to one who bought a slave on condition to free him.

(Rav Nachman bar Yitzchak): The case is, he wrote to him 'When I buy you, you are acquired to yourself from now'.

(Mishnah): If David was Mekadesh a woman to take effect after he or she converts or is freed, or after her husband dies, or after her sister (David's wife) dies, or after she will do Chalitzah, she is not Mekudeshes;

R. Meir says, she is Mekudeshes.

(Beraisa - R. Eliezer ben Yakov): Even if he said, 'These detached fruits should be Terumah on these attached fruits, or vice-versa, when they reach one-third growth and are uprooted', when they grow a third and are uprooted, this takes effect.

(Mishnah): If a woman said to her husband 'what I produce is Konam to your mouth', he need not annul this vow;

R. Akiva says, he must annul it, lest she produce more than she is obligated.

Version #1 - Question: May a woman (whose husband had no children) do Yibum based on one witness who said that her husband died?

If the reason why one witness is believed to permit a woman to remarry is because (if the husband is alive) this is prone to become known, and people do not lie about such things, here also, he would not lie!

If it is because she investigates well before marrying, here, sometimes she desires the Yavam and she will not check well!

Answer (Rav Sheshes - Mishnah): If they told her that her son died before her husband died, and she did Yibum, and later they told her the husband died first, she must leave her husband. Her children from him, both the first and last, are Mamzerim;

Question: What is the case?

Answer #1: Two witnesses told her the first time, and later two witnesses contradicted them.

Objection #1: Why would we believe the second witnesses and not the first?

Objection #2: If so, the child would be a Safek Mamzer!

Suggestion: Perhaps the Tana was not so exact.

Rejection (Seifa): The first children are Mamzerim, but later children are not.

This shows that the Tana was exact!

Answer: Rather, one witness told her the first time, and two contradicted him.

If not for the latter witnesses, one witness is believed!

Version #2: Surely, a woman may do Yibum if one witness testified that her husband died. She herself is believed to do Yibum when she says that he died!

(Mishnah): If a woman said 'my husband died' she may remarry or (in a situation of Yibum) do Yibum.

Question: May a Yevamah marry l'Shuk if one witness testified that her Yavam died?

If one witness is believed to permit a woman to marry because (if the husband is alive) this is prone to become known, and people do not lie about such things, here also, he would not lie!

If we permit an Eshes Ish because she will investigate well before marrying, here she might not check well if she hates the Yavam!