[The idea here is that a divorce has to be written on a piece of paper that says "You are herby permitted to any man," and given into her hand or her courtyard. That is the basic essence of divorce. But I must add that it must be done in front of two witnesses. Also there is a decree of the scribes that the date should be on the document.]
If a husband gives a divorce document to his wife and says that it will be valid after 30 days, and she puts it in an alley, and on the thirtieth it is still in the alley but after that it is stolen she is divorced.
This seems to be in contradiction to the Gemara in Ketuboth 86 which says the law of saying to one's wife, "This document of your divorce will be valid after 30 days," equals the law when one sells an animal and also says, "This sell will be valid after 30 days." In both cases if the object is in an alley on the thirtieth day, the transaction is valid. And the Gemara on page 82 says in the case of a sell that he must say "from now" and only then it is valid.
And in fact Tosphot says this exact fact. So the question is why does the Rambam ignore this and say "from now" only in the case of a sell, [but in the case of a divorce, he ignores this distinction.]
Rav Shach says because these are two different kinds of things. The divorce has to be in her domain or he hand and it is so on the thirtieth day. But the sell is valid by means of pulling the animal and that is no longer happening on the thirtieth day. The point of Rav Shach is clear. [The Magid Mishna says the difference is that the document in still around on the 30th day which is not the case with pulling. But it is not clear what that has to do with the need to say "from now."
[There is a possibility that this is what the Magid Mishna meant even though he did not say so openly.]
