Question: the disagreement between rabbi and r' nathan regarding the time dovid hamelech set for midnight is based on whether there are 3 or 4 mishmaros.
according to rabbi, if there are 4, of 3 hours, and dovid pushed off two, which ones did he push off, the 12-3 and 3-6? that's 6 hours, plus 2 into the morning is 8 hours? is that true?
and what is rabbi's answer, in other words how does he answer this?
why is this being brought down?
It seems to me that midnight by definition, means the middle of the night, and is not subject to any difference of opinion between Rebbi and Rebbi Nasan.
The Machlokes is whether the night consists of four Mishmaros of three hours each - Shall we say from 6 till nine, from nine till 12, from 12 till 3, and from 3 till 6 (Rebbi); or whether it consists of three Mishmaros of four hours each - from 6 till 10, from 10 till 2, and from 2 till 6 (Rebbi Nasan) - Either way, midnight will be at twelve (according to these arbitrary times.
The Gemara tries to prove Rebbi's opinion, from a combination of two Pesukim one of which informs us that Rebbi would get up at midnight, and the other, that (because the Pasuk uses the word "Mishmaros") there must have been two whole Mishmaros left until the morning; Now according to Rebbi Nasan, no two Mishmaros remained until the morning, only one and a half?
1. That Rebbi Nasan holds like Rebbi Yehoshua, who gives the time to say Keri'as Shema as the third hour (it is not clear why the Gemara learns here the third hour, and not three hours).
Consequently, from midnight until the final time to say the Shema is eight hours (six hours - one and a half Mishmaros -till the morning, plus two more hours in which to recite the Shema). Eight hours is the equivalent of two full Mishmaros, and those are the "Mishmaros" referred to by the Pasuk - not until the morning, but until the end of Zeman Keri'as Shema.
2. That even if the Pasuk would be referring to the remaining hours of night (and not until the end of Zeman Keri'as Shema), it would be correct to write "Mishmaros", because, since one and a half is more than one, it is appropriate to use the plural here.
I hope I have succeeded in clarifying the Sugya for you.
be'Virkas Gemar Chasimah Tovah to you and yours.
Sincerely
Eliezer Chrysler