[San 12a: We begin on the last line of 11a.]
The Rabbis taught in a b'raita: We do not intercalate [a month to create a leap year] in years of famine. [Rashi: The new grain cannot be used until the second day of Pesach. It was thus important not to add an extra month before Pesach, which would delay the availability of the new grain.]
It was taught in a b'raita: Rabbi says: "And there came a man from Baal-shalishah, and brought the man of God [ the prophet Elisha] bread of the first fruits, twenty loaves of barley ..." (2 Kings 4:42).
There is no place in the land of Israel in which produce ripens before Baal-shalishah, and despite that, they only brought one species of grain. You might have assumed that (he would have brought) wheat [Rashi: which ripens late], but Scripture specifies barley. You might have assumed that this occurred before the Omer [i.e., before the Omer offering that was brought on the second day of Pesach] , but Scripture teaches (in the continuation of the passage) "Give the people that they may eat", so it must have been after the Omer, [otherwise, it would not have been permissible to eat the bread].
We can conclude from this that it would have been proper to extend the year [since most of the grain had not ripened, and "Aviv" - the ripening of the grain - is one of the circumstances that justifies intercalation]. (If so) why had Elisha not extended the year? Because it was a year of famine, and people were running to the threshing floors [for grain that was desperately needed. Intercalation would have meant a extra month during which grain could not be consumed even if it were to become available.]
The Rabbis taught in a b'raita: we do not intercalate before Rosh HaShanah. [Rashi: Adar is the month that is intercalated. Were the court to decide to intercalate before Rosh HaShanah, the people might forget by the time Adar came around, six months later.] And if we did intercalate, it is not intercalated [i.e., the court's declaration is ineffective]. But in an emergency, we do intercalate immediately after Rosh HaShanah, but we only intercalate the month of Adar. [Tosaphot: Adar is biblically specified to be the twelfth month (Esther 9:1); intercalation of any earlier month would make it the thirteenth.]
[The message described below, which was transmitted at a time when Palestine was under Roman domination. includes subtle references. [The bracketed explanations are Rashi's.]
Is this so? But they (the rabbis in Palestine) sent a message to Rava (in Babylonia): A pair (of scholars) were coming from Rakat [Tiberias], and were captured by an eagle [Persian soldiers] and they they had things made in Luz. And what were these things? T'chelet [the blue wool threads used for tzitzit, imported from Luz {See Sotah 46b}. Jastrow identifies Luz as Lizan, a town in Kurdistan].
[One of the later commentators, R. Zvi Hirsh Hayos, suggests that "Luz" is an allusion to Lod, in Judea, where decisions on intercalation are known to have been taken {Yerushalmi Sanh. 1:2}. Accordingly, "T'chelet" is an allusion to the writ attesting to the court's decision to intercalate, a practice frowned on by the Roman administration.]
And by virtue of Merciful Heaven and by virtue of their own merit, they left in peace. And the appointees from Nachshon's loins [appointees of the Patriarch, who was descended from Nachshon] wanted to appoint an officer [i.e., to add a month to the year] but that Edomite [the Roman administration] did not allow them to do so. But the community leaders gathered and appointed an officer [i.e., intercalated the year] in the month in which Aaron died [the month of Av, before Rosh HaShanah].
[The extended subtle message shows that, in an emergency, a leap year could be declared before Rosh HaShanah.]
[The gemara answers:] We calculate, but we do not reveal it [i.e., the court decided to intercalate, but did not release the information, since it was too early to do so].
And how do we know that "officer" is associated with "month?" As it is written (1 Kings 4:7): "And Solomon had twelve officers over all Israel, who provided victuals for the king and his household; each man had to make provision for a month of the year."
But it is also written (1 Kings 4:19) "And one officer was in the land." [This suggests that one officer was in charge for the entire year, thus contradicting the "one-officer -- one-month" equivalence.]
Rav Yehudah and Rav Nachman (each provided an explanation): One said that a single officer was in charge of the other twelve, and the other said that the one officer refers to the intercalated month. [Both explanations restore the analogy between an officer and a month.]
We do not intercalate the year on one year for the next [Rashi:If the court foresees that the next year will require intercalation,this year they cannot intercalate this year instead. Tosaphot: If the court foresees that next year will require intercalation, it does not decide in advance to intercalate the following yearm, or - if it does - the decision is not made public].
Nor (is the year intercalated) on three consecutive years [Rashi: which would force Nisan to fall in the middle of the summer]. R. Shimon said: There was an incident involving R. Akiva, when he was in prison, and he intercalated three years consecutively. They said to him [R. Shimon]: That is evidence?! The court convened and intercalated three years at the correct time. [Rashi: R. Akiva was an expert at calendar calculations. Since he was in jail and facing the death penalty, the court met with him, and determined in advance when the next three leap years should be. They were not consecutive. This is according to the rule that intercalation can be decided in advance under duress, but the decision is not made public.]
The rabbis taught in a b'raita: We do not intercalate the year on a Sabbatical year [when crops could not be cultivated], and not in the year following the Sabbatical year.
[New grain could not be used until after the Omer offering brought on the second day of Pesach, so extending the year after the Sabbatical year would create shortages of grain].
When did they usually intercalate? In the year before the Sabbatical year [to provide extra growing time to build up stores before the Sabbatical year]. Rabban Shimon b. Gamliel's court would intercalate in the year after the Sabbatical year [Rashi: because grain could be imported].
This reflects a Tannaitic dispute, as we learned in a b'raita: We do not bring crops from outside Israel, but our rabbis permitted it. [Rabban Shimon b. Gamliel agreed with those who permitted imported crops.]
What is the dispute? R. Yirmiyah said: (Whether or not) we are concerned about clods of earth. [Earth from outside of the land of Israel is ritually impure, and can transmit impurity to food items under the same roof. Those rabbis who opposed the importation of crops were concerned that clods of earth would be embedded among the roots of plants, and might thus create impurity. But those rabbis, like Rabban Shimon b. Gamliel, who were not concerned about the possibility of such clods of earth, permitted the imports.]
The rabbis taught in a b'raita: We do not intercalate the year because of impurity. [Rashi: People who were ritually impure could not bring the Paschal sacrifice. If the court knew that the Nasi was likely to die just before Pesach {and most of the people would become ritually impure by participating in the funeral}, or if the court knew that the supply of ashes from the Red Heifer, required for ritual purification, were inadequate, they might be tempted to extend the year; the b'raita rules against such an extension.]
R. Yehudah says that we do intercalate [because of endemic impurity]. R. Yehudah said: There was an incident involving Hezekiah, King of Judea, who extended the year because of impurity, and sought Divine Mercy. [Rashi: In the time of Hezekiiah, all the population was ritually impure because they had engaged in idolatry. It would have been impossible for all the people to become ritually pure in time for Pesach unless a leap year were declared.] As it is written (II Chron 30:18-19): "For a multitude of the people, even many of Ephraim and Manasseh, Issachar and Zebulon, had not cleansed themselves, yet did they eat the passover otherwise that it is written, for Hezekiah had prayed for them saying 'The good Lord pardon [everyone that setteth his heart to seek the Lord...]" R. Shimon says: If they intercalated because of impurity, it is intercalated. So [since Hezekiah acted properly] why did he seek Divine Mercy? Because we only intercalate the month Adar, and he intercalated the month of Nisan.
R. Shimon b. Yehudah said in the name of R. Shimon: [Hezekiah sought Divine Mercy] because he persuaded the people to observe Pesach Sheni. [According to Num 9:10), individuals who were impure or were traveling on Pesach could bring the Paschal sacrifice on Pesach Sheni {the Second Pesach, one month later. Rashi: The year was not intercalated at all, but the paschal sacrifice was postponed until the second month, Iyyar {See II Chron 30:13-15}. However, this applies only to individuals; if the majority of the population was impure, they could bring the Paschal sacrifice at the proper date despite their impurity. In Hezekiah's case, the people could thus have brought the sacrifice in Nissan despite their impurity,and Hezekiah's postponement of the celebration until Pesach Sheni was wrong, which is why he sought Divine Mercy.]
[We end at the two dots on the eighth line of San 12b.]