How We Arrived at Our Current Torah Reading Schedule

It is taught in a baraita: Rabbi Shimon ben Elazar said: Ezra enacted for the Jewish people that they should read the portion of the curses that are in Leviticus before Shavuot and the portion of the curses that are in Deuteronomy before Rosh HaShana. What is the reason for this? Abaye said, and some say that it was Reish Lakish who said: In order that the year may conclude together with its curses. The Gemara asks: Granted, with regard to the curses that are recorded in Deuteronomy, there is relevance to the reason: In order that the year may conclude together with its curses, for Rosh HaShana is clearly the beginning of a new year. However, with regard to the curses that are recorded in Leviticus, what relevance does that reason have? Is that to say Shavuot is a new year? The Gemara answers: Yes, indeed, Shavuot is also a new year, as we learned in a mishna (Rosh HaShana 16a): And on Shavuot, divine judgment is made concerning the fruit of the trees.

(1) The custom prevailing through Israel is [that the reading of the Pentateuch is completed in one year. It is begun on the Sabbath after the feast of Tabernacles, when the portion commencing Bereshith "In the Beginning" (Genesis 1:1) is read.

(2) Ezra instituted the rule for Israel that the portion containing the Imprecations in the book of Leviticus (26:3-end of book) should be read before Shavuot; and those in the book of Deuteronomy (26:1-29:8) before Rosh Hashanah. The prevalent custom is to read the portion Bemidbar (Numbers 1:1-4:20) before Shavuot; Vaeschanan (Deuteronomy 3:23-7:11) after the Ninth of Av; Nitzavim (Deuteronomy 29:9-30:20) before Rosh Hashanah; Tzav (Leviticus 6:1-8:36) before Passover in an ordinary year (of twelve months). Hence, on some Sabbaths, two portions are read during the morning service, for example, Tazria (Leviticus 12:1-13:59) and Metzora (ibid. 14:1-15:33); Bechukotai (ibid. 26:3-end of book) and Behar (ibid. 25:1-26:2) etc.; the purpose being to ensure that the reading of the Pentateuch shall be completed in one year and that the portions above mentioned shall be read at their appointed periods.

We read Parashas Tzav before Pesach because Tzav talks about the scalding of vessels in order to kasher them regarding the leftover consecrated meat. Kashering vessels in this manner from chametz is learned from the consecrated meat. In a leap year, we read Parashas Metzora before Pesach because it mentions that earthenware vessels [cannot be kashered and therefore] must be broken. This is of the same topic as kashering vessels.

We read Parashas Bemidbar before Shavuos so that we interrupt between Parashas Bechukosai, which includes curses and retributions, and Shavuos, which is the day of judgement for the fruit of the tree. We don't read the curses close to such a day of judgement which would give the Satan grounds upon which to prosecute, Chas v'shalom.

Sometimes, we even read the following Parasha, Parashas Nasso, before Shavuos, (in leap years in which Rosh Hashanah starts on Thursday and both Cheshvan and Kislev have the same amount of days), in which case the schedule works out that Nasso must be read before Shavuos as well.

Tisha B'av must come before Parashas Va'eschanan so that we can read Parashas Devarim before Tisha B'av, which includes Moshe's rebukes of the nation. This way, we can read Haftaras Chazon which is the rebuke of Yishaya about the destruction of the Beis HaMikdash.

We read Parashas Nitzavim before Rosh Hashanah because it includes passages about repentance.

The following are the double-parashiyos: Vayakhel-Pekudei, Acharei Mos-Kedoshim, Tazria-Metzora, Behar-Bechukosai. These are always read together in non-leap years and are separate in leap years, except in certain configurations of the year in which Vayakhel-Pekudei is separated during non-leap years when there is an extra Shabbos before Pesach.

Chukas-Balak are only read together when the first day of Shavuos falls on Shabbos. In such a case, we have one less Shabbos to read a regular Parasha.

Mattos-Masei are only separate except in certain configurations of the year in which Acharei Mos is read before Pesach and Nasso is read before Shavuos, and we have an extra Shabbos.

Nitzavim and Vayeilech are only read separately when Rosh Hashanah falls on Monday or Tuesday.

The curses in Vayikra (i.e. Parashas Bechukosai) are read before Shavuos, and the ones in Devarim (i.e. Parashas Ki Savo) are read before Rosh Hashanah): They asked in the Beis Medrash of Rabbeinu Nissim why we divide Nitzavim-Vayeilech in a year with two Shabbosos between Rosh Hashanah and Sukkos excluding Yom Kippur. It would make sense to divide Mattos-Masei which are longer. They answered that in Parashas Nitzavim, there are curses that may apply to the Jews, and we want to finish them before Rosh Hashanah. This is difficult, because we don't consider these curses to be included in this rule, as is stated elsewhere ... that the "curses" end in Parashas Ki Savo. We can further ask, according to his reasoning, why we don't read Parashas Ha'azinu before Rosh Hashanah which also includes some curses. Therefore, the reasons seems to be that we want to separate between the curses and Rosh Hashanah by reading a parasha that does not involve the curses on the Shabbos before Rosh Hashanah. For this reason, we also read Parashas Bamidbar before Shavuos so as not to juxtapose the curses in Bechukosai and Shavuos.

From the 17th of Tammuz and on, we read the 3 haftaros of tribulation and then the 7 haftaros of consolation, and then 2 of pressure [towards doing teshuvah]. On the other Shabbosos, we read a similar topic to the Parasha​​​​​​​

Our Minhag is to say 3 haftaros of retribution before Tisha B'av ... seven of consolation afterwards and two of inspiration to do Teshuva ... this set of haftaros starts at Parashas Pinchas, and the last of the haftaros of consolation is read during Shabbos of Nitzavim, which is the Shabbos before Rosh Hashanah

Moshe decreed that Israel should from the Torah on the Sabbath, on Holidays, and that the New Moon would be like Chol Hamoed, as it is stated (Leviticus 23:44) And Moses said the appointed times (Holidays) of G-d to the Children of Israel.

If Rosh Chodesh falls on Sunday, the haftarah we read is from the book of Shmuel, starting from the pasuk "tomorrow is Rosh Chodesh." Some disagree with this custom, because we only read a haftarah that discusses matters timely to the occasion and what we derive from the Parasha, so it does not make sense to read this haftarah when it is not aligned with the parasha. Therefore, they only read מחר חודש if it is a two day Rosh Chodesh from Shabbos to Sunday. This was the custom of the great sages of France.

The reason we don't take out two Sifrei Torah every Shabbos to read the maftir of the Shabbos sacrifice like we do on Yom TOv is that we need to read the Haftarah and Maftir on Shabbos from the matter of the day, and if we read the Shabbos Korban, then we would have to read a related haftarah to Shabbos. If that is the case, all of the Haftaros would discuss a similar subject.

(4) If Rosh Hodesh Adar falls on Shabbat the portion of shekalim is read [on that day]. If it falls in the middle of the week, it is read on the Shabbat before, and on the next Shabbat there is a break. On the second [of the special Shabbatot] they read “Zakhor;” On the third the portion of the red heifer; On the fourth “This month shall be for you;” On the fifth the regular order is resumed. They interrupt [the regular order] for anything: for Rosh Hodesh, for Hanukkah, for Purim, for fasts, for Ma’amadot, and for Yom HaKippurim.

How do we read Torah for Rosh Chodesh and Chanukah that fall on Shabbos? We read seven aliyos regarding the topic of Shabbos and the eighth (i.e., maftir) aliyah on Rosh Chodesh is Bamidbar 28:9-15...