Reposted from BaltimoreJewishLife.com EXTRA
When is it a good idea to have doubles?
Most doctors and other health professionals agree with the Rambam's assessment that taking a double portion is not good for our health. Nevertheless, in most calendar years, our policy is to have several weeks when we read a double parsha so that we are able to complete the Torah every year and make a Siyum HaTorah on Simchas Torah.
There are a total of seven potential "double parshiyos," meaning parshiyos that can sometimes be read as one reading on a Shabbos. We rarely double them all in the same year. The reason for the doubling of most parshiyos is to accommodate the extra Shabbosos that are missing in a common year. The doubled parshiyos of the common year, are at the end of Sefer Shemos or in Sefer Vayikra (Vayakheil/Pekudei; Tazria/Metzora; Acharei/Kedoshim and Behar/Bechukosei) -- all of them falling between Adar, the extra month added because of a leap year, and Shavuos.
Why do we want want to "catch up" in time for Shavuos? This is so that we can fulfill a decree of Ezra, as presented in the Gemara:
Ezra decreed that the Jews read the curses of the Tochacha in Vayikra before Shavuos and those of Devarim before Rosh Hashanah. [The Gemara then queries:] Why? In order to end the year together with its curses! [The Gemara then comments:] We well understand why we read the Tochacha of Devarim before Rosh Hashanah because the year is ending, but why is that of Vayikra read before Shavuos? Is Shavuos the beginning of a year? Yes, Shavuos is the beginning of a new year, as the Mishnah explains that the world is judged on Shavuos for its fruit.” Tosafos (ad loc.) explains the Gemara to mean that the tochacha should be completed two weeks before each "New Year" to allow a week as a buffer between the tochacha and the beginning of the year. Therefore, the parsha of Bechukosei, which includes the tochacha, should be read at least two weeks before Shavuos, thus necessitating combining the parshiyos in a way that we complete them and are able to read Bamidbar before Shavuos. While it is ideal that there should be one Shabbos, Bamidbar, between the tochacha of Bechukosei and Shavuos, in some leap years, there are two such Shabbosos, and Naso is also read before Shavuos.
However, there are three other "double parshiyos" that do not fall during this part of the year, each pair having its own specific reason, unrelated to the leap year, for being combined.
The "Double Parsha of the Exile"
Chukas-Balak is a double parsha that exists only outside Eretz Yisrael. I once heard it jokingly referred to as "Parsha Sheniyah shel Galiyus," The Double Parsha of the Exile, a takeoff on the halachic term "Yom Tov Sheini shel Galiyus," the second day of Yom Tov that is observed outside Eretz Yisrael. Indeed, this second day is the reason for combining Chukas and Balak into one parsha: when Shavous falls on a Friday, its second day falls on a Shabbos, and therefore the communities of the exile read Aseir te'aseir in Parshas Re'eih, because it discusses the Yom Tov, whereas in Eretz Yisrael the next week's parsha, Naso, is read, since it is no longer Shavuos. When this phenomenon occurs, the Jewish communities of Eretz Yisrael and of the Golah are reading different parshiyos for four weeks, from Parshas Naso through Parshas Chukas, with Eretz Yisrael always reading the parsha a week earlier. The Golah "catches up" on the Shabbos that falls on the 12th of Tamuz by reading both Chukas and Balak on one Shabbos, while in Eretz Yisrael, they read only Parshas Balak. Thus, the following week, both communities read Parshas Pinchas.
There are two other parshiyos, Matos and Masei, which are almost always read together, and are separated only when the year requires an extra Shabbos reading. Although we treat Matos and Masei as separate parshiyos, we should really view them as one long parsha (making the combination the largest parsha in the Torah) that occasionally needs to be divided to accommodate the need for an extra Torah reading.
On the occasional years when Matos and Masei are read separately, Parshas Pinchas falls before the Three Weeks -- and we actually read the haftarah that is printed in the chumashim for Parshas Pinchas, Ve'yad Hashem, from the book of Melachim. In all other years, Parshas Pinchas is the first Shabbos of the Three Weeks, and the haftarah read is Divrei Yirmiyahu, the opening words of the book of Yirmiyahu, which is appropriate to the season.
The printers of chumashim usually elect to print Divrei Yirmiyahu as if it is the haftarah for Parshas Matos, and then instruct you to read it on most years as the haftarah for Pinchas. It would be more logical to label the haftarah Divrei Yirmiyahu as the one appropriate for the first of the Three Weeks, and to print two haftaros after Parshas Pinchas: one (Ve’yad Hashem) for the occasional year when Pinchas falls before the 17th of Tamuz, and the other (Divrei Yirmiyahu) for the far more frequent occurrence of a year in which Pinchas falls after the 17th of Tammuz. Readers should be instructed that when Parshas Matos and Parshas Masei are read on separate weeks, that the haftarah for Parshas Matos is the second haftarah printed after Parshas Pinchas. But, alas, the printers do not usually consult with me, but simply look at what other printers have done.
In what years are Matos and Masei separated? Only in leap years and only when there are no parshiyos doubled together from Simchas Torah until the week before Rosh Hashanah. (I will explain shortly why Parshas Netzavim is treated differently.) There are two types of leap years that require Matos and Masei to be separated:
(1) A leap year that begins on a Thursday.
A leap year adds an extra month, which is thirty days, not 28. Thus, a leap year sometimes adds five extra Shabbosos, not just four, and there is a need to add an extra reading. This occurs when a leap year begins on a Thursday -- in calendar jargon, the years××× and ××©×, which both mean that Rosh Hashanah falls on a Thursday. In these years, to accommodate the extra Shabbos, the parshiyos of Matos and Masei are separated.
(2) There is one other situation in Eretz Yisrael in which the parshiyos of Matos and Masei are read on separate weeks, without which, there would simply not be enough readings for every Shabbos of the year. When Rosh Hashanah of a leap year falls on Tuesday, or in some leap years even when it falls on Monday, Eretz Yisrael has to read every possible separate parsha from Rosh Hashanah until the next Rosh Hashanah to accommodate all the Shabbosos of the year. In these years, in Eretz Yisrael there are no doubled parshiyos, and therefore Matos and Masei are separated.
Why is this dependent on being in Eretz Yisrael? The year is the same length no matter where you are, and there seem to be just as many Shabbosos in Eretz Yisrael as there are outside.
The difference is that, in these years, the Eighth Day of Pesach, Acharon shel Pesach, falls on Shabbos. On this Yom Tov day, observed only outside Eretz Yisrael, the special Yom Tov reading in Chutz LaAretz is Aseir te'aseir, whereas in Eretz Yisrael this Shabbos is after Pesach (although the house is still chometz-free!) and the reading is Parshas Acharei Mos. Thus, in Chutz LaAretz there is a need to double a parsha, and, according to what is today common practice, that parsha is Matos and Masei.
The practice I just mentioned, however, creates a very unusual phenomenon:
On the subsequent Shabbos (i.e., one week after Pesach ends), the Jews of Eretz Yisrael are already reading Parshas Kedoshim, whereas outside Eretz Yisrael the reading is Parshas Acharei Mos. The communities outside Eretz Yisrael ignore the opportunity of doubling up parshiyos Acharei/Kedoshim, Behar/Bechukosei and Chukas/Balak, all of which are doubled together on other occasions, and wait until the very last parsha of Bamidbar to combine Matos with Masei. Thus, the disparity between Eretz Yisrael and Chutz LaAretz lasts for over three months. By the way, this phenomenon is fast approaching. Hebrew year 5776, three years from now, follows this pattern, so that those who return to Chutz LaAretz after spending Pesach in Eretz Yisrael will find that they have missed a parsha. Unless, of course, they decide to stay in Eretz Yisrael until the Nine Days.
This leads to a very interesting question: Why is the disparity between Eretz Yisrael and Chutz LaAretz allowed to last for such a long period of time? There are three potential doubled parshiyos that are passed before one gets to Parshas Matos – all weeks in which those in Chutz LaAretz could combine two parshiyos in order to catch up.
As you can imagine, we are not the first to raise this question, which is indeed raised by one of the great sixteenth century poskim, the Maharit (Shu’t Volume II Number 4). He answers that Shavuos should ideally fall between Bamidbar and Naso, and that combining either Acharei Mos with Kedoshim, or Behar with Bechukosai would push Shavuos until after Parshas Naso.
However, the Maharit points out that this does not explain why the parshiyos of Chukas and Balak are not combined, although he notes that the Syrian communities, indeed, follow this practice — that is, in a leap year when Acharon shel Pesach falls on Shabbos, the Syrian community combines parshiyos Chukas and Balak together, but reads Matos and Masei on separate weeks, as is done in Eretz Yisrael.
To explain why the parshiyos of Chukas and Balak are not combined, the Maharit concludes that once most of the summer has passed and the difference is only what to read on the three Shabbosos that end the reading of Sefer Bamidbar, we combine Matos with Masei, which are usually combined, rather than Chukas and Balak, which are usually separate.
Netzavim – Vayeilech
We have now explained the reason for every instance in which we read a double parsha, with one important and anomalous exception – the two tiny parshiyos of Netzavim and Vayeilech. Tosafos already asks why we often combine together the two huge parshiyos of Matos and Masei, and in the very same year we read the two tiny parshiyos of Netzavim and Vayeilech on separate weeks. His answer is based on his explanation to the Gemara that we quoted earlier: Ezra decreed that the Jews read the curses of the Tochacha in Vayikra before Shavuos and those of Devarim before Rosh Hashanah. [The Gemara then queries:] Why? In order to end the year together with its curses, which Tosafos understood to mean that the tochacha should be completed two weeks before Rosh Hashanah, to allow a week as a buffer between the tochacha and the beginning of the year. That buffer parsha is Netzavim, which must always be read on the last Shabbos of the year, but ultimately means that only a small part of the Torah is left to be read between Rosh Hashanah and Simchas HaTorah. This small part left is divided into three small parshiyos, Vayeilech, Haazinu, and Vezos Haberacha. Vezos Haberacha is, of course, read on Simchas HaTorah, and Haazinu on the last Shabbos of the cycle, which is either Shabbos Shuva or the Shabbos between Yom Kippur and Sukkos, if there is one. Thus, whether Vayeilech merits its own Shabbos or is combined with Netzavim depends on one and only one factor: Is there more than one Shabbos between Rosh Hashanah and Sukkos? When there are two such Shabbosos, then Vayeilech is read on Shabbos Shuva, and Haazinu the week afterwards. When there is only one Shabbos that does not fall on a Yom Tov between Rosh Hashanah and Sukkos, Vayeilech is combined with Netzavim on the week before Rosh Hashanah and Haazinu is read the week of Shabbos Shuva.
From all of the above, we see the importance that Chazal placed on the public reading of the Torah and of completing its cycle annually. It goes without saying that we should be concerned with being attentive to the words of the Torah as they are being read, and that the baal keriah should make every effort to read them accurately.
 Megillah 31b; Rambam, Hilchos Tefillah 13:2
 The Levush explains that, without the week as a buffer, Satan could use the tochacha as a means of prosecuting against us on the judgment day.
 Any given year can be scheduled in fourteen different ways, and each of these years is identified by this three-letter system. The first letter corresponds to the day of the week on which Rosh Hashanah falls in that year; the third letter corresponds to the day of the week of the first day of Pesach. The second letter identifies whether the year is chaseirah, lacking or defective; kesidrah, expected or regular; or sheleimah full or excessive. In a different article, entitled The Creation of the "Permanent" Calendar, I explained exactly what this means and why and how it happens.