If he says to her, "Behold this is your get if I don't come [back] within 30 days," or he says, "On condition that I don't come [back] within 30 days," and he is on the way to come back within 30 days but he gets sick or he is prevented because of a river, and he only comes after 30 days, the bill of divorce takes effect, even if he stands and protests, "I was an oneis [the events were not in his control]!" For there is no oneis in regard to divorce. And [this is so] even though his intent was openly known that he did not want to divorce, since he did not stipulate "except for the case if I become an oneis." But an oneis that is very uncommon, such as being attacked by a lion or being bitten by a snake or a house fell on him, he never intended for that to make a condition on, and the bill of divorce is void [and if he dies] she is bound to the yibbum [levirate marriage]. Rem"a: And if he becomes a captive, that is a common oneis, and the bill of divorce is not void because he did not stipulate [the exception] (Mordechai Perek Mi Sheachzo).
"Behold this is your bill of divorce if I don't come [back] from this point [mi'kan] for 12 months," and he didn't say "from now" [me'achshav] and [he didn't say] "on condition" [al menat], and he dies within 12 months, this is a doubt, and she must do chalitza and not yibbum.
"Behold this is your bill of divorce from now [me'achshav], if I don't come [back] from this point [mi'kan] for 12 months." And he dies within 12 months, she is divorced. But if there is a yibbum to her, she cannot remarry with chalitza until 12 months pass. If she doesget remarried, she does not [get forced to] leave [her second husband].
If he gave the bill of divorce at night and said to her, "Behold this is your bill of divorce on condition [al menat] the sun emerges from its sheath, and he dies at night, the bill of divorce take effect. But if he said to her [instead of al menat] "if the sun emerges from its sheath] or he says, "when the sun emerges from its sheath," and he dies at night, it is doubtful. Some say that even [the phrase] "al menat" should be treated stringently, unless he said "from now [will this bill of divorce take effect on condition...", explicitly.
He said, "If I don't come [back] in 12 months [from now] write a Get for my wife." Or, if he says, "Write a Get and give it to my wife if I don't come [back] in 12 months, we don't write it within the 12 months, even if they don't want to give it until after 12 months. And if they write it within the 12 months, in spite of the fact that they give it to her after the 12 months, it is not a [valid] Get. [If] they wrote it and they gave it to her after 12 months, and he dies, if his death precedes the giving of the Get, it is not a [valid] Get. And if the Get [is given] before death, then it is a [valid] Get (Tur). And if there is a doubt as to which came first, then there is a doubtful divorce. Gloss: [If] they didn't give it to her immediately after 12 months, rather it was a long time afterwards, in spite of the fact that it was impeded by the wife who did not want to accept it immediately, even so it is a [valid] Get, and that is only if the husband is alive. (Go look in the Beit Yosef):
If he said, "Write and give a bill of divorce to my wife after the week," they only write until a year after the week. If he said, "After a year," they only write until a month into the second year. If he said, "After a month," they only write until the Sabbath into the second month. If he said, "After the Sabbath," they only write until the end of Tuesday. If he said, "Write and give it to her before the Sabbath", they write it from Wednesday to the end of Friday, and give it to her. If they delayed past the times that he told them, and then they wrote and gave it to her, she is doubtfully divorced. Rem"a: Some say that if he said, "After 12 months," its as if he said, "After a year." If he saif "After 30 days," they write one day after the 30th day (Hagahot Alfasi Perek Mi Sheachzo).
if he made a condition that if he does not pass before her for 30 days she is divorced, and he walks about and does not seclude himself with her, once 30 days pass she is considered divorced; this is true even if he passes her during the 30 days but does not seclude himself with her, it is still a kosher get (divorce document).When is this said? Only when he says "she is to be believed when she says I did not appease her". But if she is not believed by him, then we are concerned perhaps he appeased her while passing her, and he forgave her, and the get was annulled- making the get invalid. Similarly, one who says to a woman "here is your get, it goes into effect in 12 months", and he remained with her in the city, we are concerned that perhaps he appeased her, until he declares "she is believed by me to say that she has not been appeased". This similarly applies to all condition [of a get] that are contingent on her willingness. And if she is willing, and she forgives the conditions for her husband, the get is nullified, because we are worried perhaps he appeased her, until he says "she is believed by me". When is this said? When she is divorced after nisuin (meaning from a full marriage), and he is considered familiar and comfortable with her. However, if the divorce is from erusin (betrothal), we are not concerned that she maybe she was appeased by him. I he says "here is your get, if I don't return within 12 months", we aren't concerned that he returned in a secretive manner, because that is not the normal way of people. So if the set time (i.e. 12 months) passed, she is divorced. Some say that even in such a case we are concerned that he came back secretively, unless his condition included the fact that his wife is to be believed if she says he didn't return. It is appropriate to ideally be concerned about this opinion, and such is the custom, that he should include in the condition that she is believed to say that he didn't return. And is the condition was that his return must be corroborated by witnesses, and the time passed and no witnesses came forward that he returned, according to all opinions we are not concerned that he came, even if he did not indicate that his wife is reliable.