(Mishnah): If one sent a Get to his wife, and he caught up with the Shali'ach or he sent a Shali'ach to the first Shali'ach, and told him (himself, or through the second Shali'ach) 'the Get that I gave to you is Batel', it is Batel;

If he came to his wife before [she received the Get], or he sent a Shali'ach to her and told her 'the Get that I sent to you is Batel', it is Batel;

Once she received the Get, he cannot invalidate it.

(Gemara) Question: Does this not argue with Reish Lakish? Reish Lakish said that one cannot be Mevatel his Shelichus verbally! (Why does Bitul work? - SEFER NIR)

Answer: It is due to a stringency of Arayos. (Mid'Oraisa, it is not Batel and she is divorced! Perhaps we are stringent lest people think that she is divorced even if he was Mevatel in Beis Din. In Halachah 2, we explain that Bitul in Beis Din is like an action, and it takes effect. - PF)

If one made a Shali'ach to bring a Get, he must give it to her in front of two [witnesses], and the Shali'ach does not count towards the two. (RASHBA 32a - we discuss a Shali'ach to or from Chutz la'Aretz, or from one Medinah to another, so he must say the declaration.)

If the [second] Shali'ach went to be Mevatel the Get, he must be Mevatel in front of two, and the Shali'ach counts towards the two.

Question: [The husband] went to be Mevatel the Get, and found [the Shali'ach] in the street, and said 'the Get that I gave to you [did you give it to her]?' He said, I brought it to her.

While he was talking with him, [the Get] fell from [the Shali'ach]. He said, didn't you say 'I brought it to her?' He said, I brought it to her, and she said 'it should be [a deposit] in your hand.' What is the law?

2. Since [the Shali'ach] has the ability to divorce, he is believed (the husband cannot nullify it);

Note: SHIREI KORBAN says that even now, the Shali'ach can give it to her. Her husband can be Mevatel it now front of her or the Shali'ach, so the Shali'ach cannot divorce her; he could only give it to her, and her husband will not be able to prove that she did not receive it before Bitul. The Gemara says that he can divorce her. A clever husband would immediately go to her, with witnesses, and say 'should I divorce you now?' Presumably, her response will reveal whether or not she already received it. I prefer to explain like PNEI MOSHE, that he had the ability to divorce her. Perhaps the text should say 'she'Hayah b'Yado.'

Or, since [the Get] is found in his hand, he is not believed?

Question: If the Shali'ach [to be Mevatel the first Shali'ach] fell sick, how do you judge this - like Gitin or Kidushin?

Note: MORDECHAI (Kidushin 505) says that any Shelichus that requires another's consent, it is called Mili, and a Shali'ach cannot make another Shali'ach for Mili. If so, Bitul is like divorce; it does not need another's consent. Why should we judge it like Kidushin? Others say that Shelichus without an item is called Mili (in MORDECHAI Gitin 420); if so, Bitul is like Shelichus for Kidushin when no item was given. However, the next line of Gemara connotes like the first side. (PF)

If you judge this like Gitin, anyone can divorce [so he can make another Shali'ach]. If you judge this like Kidushin, not anyone can divorce [so he cannot make another Shali'ach].