Selection of Mishnayos Relating to Korban HaOmer (5780)

This source sheet is the second part of in a Series of source sheets focusing on different aspects of the Holiday of Pesach as seen through the Mishnah. This sheet will focus on the Mitzvah of Korban Omer.

Color Code for the Mishnah: Case: Black; Ruling: Green or Red; Name of Tanna: Gold; Reason: Blue; Condition: Purple; Proof: Grey ; Rule: Fuscia

The Korban HaOmer

The Torah tells us in Parshas Emor:*

וַיְדַבֵּ֥ר יי אֶל־מֹשֶׁ֥ה לֵּאמֹֽר׃ (י) דַּבֵּ֞ר אֶל־בְּנֵ֤י יִשְׂרָאֵל֙ וְאָמַרְתָּ֣ אֲלֵקֶ֔ם כִּֽי־תָבֹ֣אוּ אֶל־הָאָ֗רֶץ אֲשֶׁ֤ר אֲנִי֙ נֹתֵ֣ן לָכֶ֔ם וּקְצַרְתֶּ֖ם אֶת־קְצִירָ֑הּ וַהֲבֵאתֶ֥ם אֶת־עֹ֛מֶר רֵאשִׁ֥ית קְצִירְכֶ֖ם אֶל־הַכֹּהֵֽן׃ (יא) וְהֵנִ֧יף אֶת־הָעֹ֛מֶר לִפְנֵ֥י יי לִֽרְצֹנְכֶ֑ם מִֽמָּחֳרַת֙ הַשַּׁבָּ֔ת יְנִיפֶ֖נּוּ הַכֹּהֵֽן׃ (יב) וַעֲשִׂיתֶ֕ם בְּי֥וֹם הֲנִֽיפְכֶ֖ם אֶת־הָעֹ֑מֶר כֶּ֣בֶשׂ תָּמִ֧ים בֶּן־שְׁנָת֛וֹ לְעֹלָ֖ה לַיי (יג) וּמִנְחָתוֹ֩ שְׁנֵ֨י עֶשְׂרֹנִ֜ים סֹ֣לֶת בְּלוּלָ֥ה בַשֶּׁ֛מֶן אִשֶּׁ֥ה לַיי רֵ֣יחַ נִיחֹ֑חַ וְנִסְכֹּ֥ה יַ֖יִן רְבִיעִ֥ת הַהִֽין׃ (יד) וְלֶחֶם֩ וְקָלִ֨י וְכַרְמֶ֜ל לֹ֣א תֹֽאכְל֗וּ עַד־עֶ֙צֶם֙ הַיּ֣וֹם הַזֶּ֔ה עַ֚ד הֲבִ֣יאֲכֶ֔ם אֶת־קָרְבַּ֖ן אֱלֹקֵיכֶ֑ם חֻקַּ֤ת עוֹלָם֙ לְדֹרֹ֣תֵיכֶ֔ם בְּכֹ֖ל מֹשְׁבֹֽתֵיכֶֽם׃ (ס) (טו) וּסְפַרְתֶּ֤ם לָכֶם֙ מִמָּחֳרַ֣ת הַשַּׁבָּ֔ת מִיּוֹם֙ הֲבִ֣יאֲכֶ֔ם אֶת־עֹ֖מֶר הַתְּנוּפָ֑ה שֶׁ֥בַע שַׁבָּת֖וֹת תְּמִימֹ֥ת תִּהְיֶֽינָה׃ (טז) עַ֣ד מִֽמָּחֳרַ֤ת הַשַּׁבָּת֙ הַשְּׁבִיעִ֔ת תִּסְפְּר֖וּ חֲמִשִּׁ֣ים י֑וֹם וְהִקְרַבְתֶּ֛ם מִנְחָ֥ה חֲדָשָׁ֖ה לַיי

On מִֽמָּחֳרַ֤ת הַשַּׁבָּת֙ we are commanded to bring a special Korban Mincha (a Korban made from grain) called the Korban Omer--which is to be brought specifically from the new grain crop. Besides for the many Halachos about the Korban itself, the bringing of the Korban acts as a trigger for many other Mitzvos as well.

Halochos of the Korban Omer

  1. As noted, the Korban Omer is brought from the new grain, specifically barley (which ripens around Pesach time).
  2. The barley must be from Eretz Yisroel and, in fact, this requirement is what differentiates the holiness of Eretz Yisroel over other lands. (see Keilim 1:6).
  3. It is supposed to come from the first harvest as well, therefore, it is generally prohibited, with some exceptions, to harvest grain in Eretz Yisroel prior to the bringing of the Korban Omer.
  4. It is to be harvested at night but, if harvested during the day, the Korban is kosher.
  5. The harvesting and bringing of the Korban Omer was done with great fanfare and even pushes aside shabbos.
  6. The grains were roasted and then ground into fine flour.

Other Mitzvos Tied to the Korban Omer

  1. Prior to the bringing of this Korban, it is prohibited to eat from the new crop of grain (i.e., any grain that has taken root since the prior year's Korban). This is called חדש. Essentially, any grain grown after last year’s Korban Omer remains prohibited to eat until after this year’s Korban is offered. Today, in the absence of the Beis Hamikdash, we wait until the night after the 16th (or outside Eretz Yisroel, the 17th) of Nissan to partake in new grain. As a practical matter, since we do not use grain on Pesach, we wait until after Pesach to eat new grain.
  2. Starting from the night we harvest the Korban Omer, the Torah tells us to count seven full weeks (Sefiras HaOmer), 49 days. On the 50th day (which is the Yom Tom of Shavuos), we are to bring another Korban Mincha, this one is called the Shtei HaLechem (the two loaves of bread). This Mincha comes from wheat (not barley) and is the first new wheat brought in the Beis HaMikdash. Prior to this date, no Korban can be brought from the new Harvest.

ממחרת השבת

When exactly (i.e., which day) the Korban Omer was to be brought was the subject of a great dispute during the times of the Second Beis Hamikdash. As will be described in greater detail below (Mishna Menachos 10:3), according to the Chachomim/Perushim/Pharisees, ממחרת השבת was defined as the 16th of Nissan, the second day of Pesach. The "Shabbos" being referred to in the Pasuk was understood to mean Pesach. On the other hand, the various sects (Tziddukim (Saducees), Boethusians and Essenes) took the Torah's words literally so that, in their calendar, the Korban Omer was always brought on the Sunday following the first day of Pesach. This later group would try and make the first day of Pesach fall on a Shabbos so that Sunday would fall out on the 16th of Nissan.

Below, is a selection of Mishnayos from the 10th Perek of Menachos describing aspects of the Korban Omer. It certainly does not cover every aspect of the Korban but provides sufficient background for the interested reader to explore further. Additional source materials can be found at

*The purple highlighted passages represent Positive Mitzvos; Red are Negative Mitzvos.

Introduction to Mishna 10:3-4

The following two Mishnayos describe the process of harvesting, preparing and bringing of the Korban Omer. It would start prior to Pesach when the court would send out people to bundle the grain (while it was standing) so that it would be easier and faster to reap at night. The barley had to be roasted before being ground and sifted (13 times!). Once the flour was made it was mixed with oil, layered with frankincense, waived and a portion was offered on the Alter. The rest would be eaten by the Kohanim.

The Mishna describes the fanfare associated with the harvesting ceremony. People would gather on the night after the first day of Pesach in the fields outside Yerushalyim and watch as the barley was harvested. There was significant audience participation in this event and the mood was particularly joyous. There were a number of reasons for this. First, as noted, the harvest took place during the holiday of Pesach and the people were already in a joyous mood. Second, the Omer signified the start of the harvesting season. Third, as specifically mentioned in the Mishna and as is described in detail below, the proper date of the Korban Omer was a point of contention and the Chachomim, by including the general population, sought to solidify their viewpoint that the proper date to bring the Korban Omer was the eve of the 16th of Nissan.

Because the Korban Omer was a public offering, the barley from which it was brought was paid for by the public coffers (See Shekalim 4:1). Because only a small portion of the extracted flour was needed for the Korban Omer, the residual could be purchased and redeemed by anyone. Once redeemed, any dough made from the flour was subject to the obligation of Challah [the requirement to give a potion of every dough to the Kohein]. The end of Mishna 4 describes a dispute over whether the redeemed flour is obligated in Terumos and Maasros. The Chachomim say it is not obligated since at the time the obligation comes into being (i.e., the obligation to give Terumos and Ma'asros arises once the winnowed pile of grain is smoothed over) the grain was owned by Hekdesh. Whereas, according the Rabi Akiva, from the onset, Hekdesh only wanted to purchase the limited amount of flour needed for the Korban, therefore, the residual flour was never purchased by Hekdesh--hence the flour was subject to Ma’asros from the very beginning.

The Different Jewish Sects

Towards the second half of the second Beis HaMikdash a number of different groups (sects) of Jews developed, including the Tziddukim (Saducees), Boethusians and Essenes. The Chachomim were known as Peirushim (Pharisees). Throughout the Mishnayos we find a number of disagreements between these groups and the Chachomim. One of the most famous and contentious fights was over the day on which the Korban Omer was to be brought.

Traditional sources relate that the Sadducian sect was started by a wayward student of Antigonus Ish Socho named Tzadok. He misinterpreted one of his Rebbe's teachings and could not reconcile it with his faith. It is commonly misunderstood that that the Sadducees only believed in or followed exclusively the Torah Sh'beksav, the Written Torah (like the Karaites of the Middle Ages). However, as it appears in various Mishnayos, while they had their own distinctive way of explicating the Torah and its laws--often adhering to a more Peshat level understanding of the text--they did have an interpretive tradition. Many of their leaders were active in the Beis HaMikdash and the Beis Midrash and, more importantly, there likely was not a singular set of Halochos they all followed. In addition, while not identical, the Qumran sect espoused similar Halachik positions. See generally, Eyal Regev, הצדוקים והלכתם: על דת וחברה בימי בית שני, יד יצחק בן צבי, ירושלים תשס"ה and Yair Furstenberg, "קובלין אנו עליכם פרושים: לעיצובה של תמונת העולם הפרושית במשנה", א' רוזנק וד' שרייבר (עורכים), ההלכה: הקשרים רעיוניים ואידיאולוגיים גלויים וסמויים, מגנס וואן ליר, ירושלים תשע"ב, עמ' 283-211

Korban Omer

In describing the day on which to bring the Korban the Torah uses the term "מִֽמָּחֳרַת֙ הַשַּׁבָּ֔ת," the day after "shabbos." The Chachomim had a tradition that this meant the day after the first day of Pesach (i.e., the second day of Pesach). Whereas, the Boethusians, relying on a literal translation of the words held that the Korban was meant to be brought on the Sunday following the first day of Pesach (this would mean that the date of the Korban was not fixed and it would depend on when Pesach fell--but it would always be a Sunday, as would Shavuous). Importantly, this also meant that according to the Boethusians the harvesting of the Omer would never fall on Shabbos, requiring the potential desecration of Shabbos, something they generally would try and avoid at all costs.

The only time these two group would agree that the Korban be brought on the same day was when the first day of Pesach fell on Shabbos. Then, according to all, the Korban Omer was brought the next day, Sunday, the second day of Pesach. In order to make sure this would happen, the Boethusians would try to make sure that Rosh Chodesh Nissan fell on a Shabbos--at times that would mean having witnesses say they saw the new moon on Friday night even if they had not. Our Mishna tells us that once this started happening, the Beis Din would only rely on witnesses that were known not to be Boethusians. (See Rosh Hashana 2:1)

Notably, we do not find specific cases of the Pharisees directly challenging the logic of the Sadducian Halacha, rather, you find numerous instances of the Pharisees (and the later Chachomim) taking actions to indoctrinate their own views and solidify its practice. For example, our case of the harvesting of the Omer, the procession and the triple repeat of the instructions ensured that no one forgot the law. Similarly, we find the Chachomim admonishing the Kohein Godol prior to Yom Kippur to properly observe the Incense Service. Finally, when it came to the Parah Adumah, the Chachomim would specifically make the Kohein designated to burn the Heifer a "T'vul Yom" so as to clearly indicate that the Halacha was not like the Sadducees.

כֵּיצַד הָיוּ עוֹשִׂים.

שְׁלוּחֵי בֵית דִּין יוֹצְאִים מֵעֶרֶב יוֹם טוֹב, וְעוֹשִׂים אוֹתוֹ כְרִיכוֹת בִּמְחֻבָּר לַקַּרְקַע, כְּדֵי שֶׁיְּהֵא נוֹחַ לִקְצֹר.

וְכָל הָעֲיָרוֹת הַסְּמוּכוֹת לְשָׁם, מִתְכַּנְּסוֹת לְשָׁם, כְּדֵי שֶׁיְּהֵא נִקְצָר בְּעֵסֶק גָּדוֹל.

כֵּיוָן שֶׁחֲשֵׁכָה, אוֹמֵר לָהֶם, בָּא הַשָּׁמֶשׁ, אוֹמְרִים, הֵן. בָּא הַשָּׁמֶשׁ, אוֹמְרִים הֵן.

מַגָּל זוֹ, אוֹמְרִים הֵן. מַגָּל זוֹ, אוֹמְרִים הֵן.

קֻפָּה זוֹ, אוֹמְרִים הֵן. קֻפָּה זוֹ, אוֹמְרִים הֵן.
בְּשַׁבָּת אוֹמֵר לָהֶם, שַׁבָּת זוֹ, אוֹמְרִים הֵן. שַׁבָּת זוֹ, אוֹמְרִים הֵן.
אֶקְצֹר, וְהֵם אוֹמְרִים לוֹ קְצֹר. אֶקְצֹר, וְהֵם אוֹמְרִים לוֹ קְצֹר.
שָׁלשׁ פְּעָמִים עַל כָּל דָּבָר וְדָבָר, וְהֵם אוֹמְרִים לוֹ הֵן, הֵן, הֵן.
וְכָל כָּךְ לָמָּה. מִפְּנֵי הַבַּיְתוֹסִים, שֶׁהָיוּ אוֹמְרִים, אֵין קְצִירַת הָעֹמֶר בְּמוֹצָאֵי יוֹם טוֹב:

(3) How would they do it [reap the omer]?The agents of the court used to go out on the day before the festival and tie the unreaped grain in bunches to make it the easier to reap. All the inhabitants of the towns near by assembled there, so that it might be reaped with a great demonstration. As soon as it became dark he says to them: “Has the sun set?” And they answer, “Yes.” “Has the sun set?” And they answer, “Yes.” “With this sickle?” And they answer, “Yes.” “With this sickle?” And they answer, “Yes.” “Into this basket?” And they answer, “Yes.” “Into this basket?” And they answer, “Yes.” On the Sabbath he says to them, “On this Sabbath?” And they answer, “Yes.” “On this Sabbath?” And they answer, “Yes.” “Shall I reap?” And they answer, “Reap.” “Shall I reap?” And they answer, “Reap.” He repeated every matter three times, and they answer, “yes, yes, yes.” And why all of this? Because of the Boethusians who held that the reaping of the omer was not to take place at the conclusion of the [first day of the] festival.

קְצָרוּהוּ וּנְתָנוּהוּ בְקֻפּוֹת,

הֱבִיאוּהוּ לָעֲזָרָה,

הָיוּ מְהַבְהְבִין אוֹתוֹ בָאוּר, כְּדֵי לְקַיֵּם בּוֹ מִצְוַת קָלִי, דִּבְרֵי רַבִּי מֵאִיר.

וַחֲכָמִים אוֹמְרִים, בְּקָנִים וּבִקְלִיחוֹת חוֹבְטִים אוֹתוֹ, כְּדֵי שֶׁלֹּא יִתְמָעֵךְ.

נְתָנוּהוּ לָאַבּוּב, וְאַבּוּב הָיָה מְנֻקָּב, כְּדֵי שֶׁיְּהֵא הָאוּר שׁוֹלֵט בְּכֻלּוֹ.
שְׁטָחוּהוּ בָעֲזָרָה, וְהָרוּחַ מְנַשֶּׁבֶת בּוֹ.

נְתָנוּהוּ בְרֵחַיִם שֶׁל גָּרוֹסוֹת, וְהוֹצִיאוּ מִמֶּנּוּ עִשָּׂרוֹן שֶׁהוּא מְנֻפֶּה מִשְּׁלשׁ עֶשְׂרֵה נָפָה,
וְהַשְּׁאָר נִפְדֶּה וְנֶאֱכָל לְכָל אָדָם.

וְחַיָּב בַּחַלָּה, וּפָטוּר מִן הַמַּעַשְׂרוֹת.

רַבִּי עֲקִיבָא מְחַיֵּב בַּחַלָּה וּבַמַּעַשְׂרוֹת.
בָא לוֹ לָעִשָּׂרוֹן, וְנָתַן שַׁמְנוֹ וּלְבוֹנָתוֹ, יָצַק, וּבָלַל, הֵנִיף, וְהִגִּישׁ, וְקָמַץ, וְהִקְטִיר, וְהַשְּׁאָר נֶאֱכָל לַכֹּהֲנִים:

(4) They reaped it, put it into the baskets, and brought it to the Temple courtyard; Then they would parch it with fire in order to fulfill the mitzvah that it should be parched [with fire], the words of Rabbi Meir. But the sages say: they beat it with reeds or stems of plants that the grains should not be crushed, and then they put it into a pipe that was perforated so that the fire might take hold of all of it. They spread it out in the Temple courtyard so that the wind might blow over it. Then they put it into a gristmill and took out of it a tenth [of an ephah of flour] which was sifted through thirteen sieves. What was left over was redeemed and might be eaten by any one; It was liable for hallah but exempt from tithes. Rabbi Akiba made it liable both to hallah and to tithes. He then came to the tenth, put in its oil and its frankincense, poured in the oil, mixed it, waved it, brought it near [to the altar], took from it the handful and burnt it; and the remainder was eaten by the priests.

Introduction to Mishna 10:7

The Chachomim identified five main grains: wheat, barley, spelt, oats* and rye which are subject to a number of Halachos. These grains can be used for Matzoh and, alternatively, can become Chametz. Dough made from these grains are subject to the laws of Challah.** According to our Mishna, the dough need not be made from a single grain--in other words you can combine grains to make Challah-eligible dough.

The bringing of the Korban Omer acts as a trigger to permit two, otherwise prohibited actions. First, the Mishna tells us that these grains are subject to the rules of Chadash. The Pasuk tells us וְלֶחֶם֩ וְקָלִ֨י וְכַרְמֶ֜ל לֹ֣א תֹֽאכְל֗וּ עַד־עֶ֙צֶם֙ הַיּ֣וֹם הַזֶּ֔ה עַ֚ד הֲבִ֣יאֲכֶ֔ם אֶת־קָרְבַּ֖ן--it is prohibited to eat from these new grains prior to the bringing of the Korban Omer. This prohibition applies even nowadays--even without a Beis HaMikdash. As we will see in Mishna 5, this prohibition lasts until day’s end on the 16th (or 17th) of Nissan. Then, all new grain is permissible to consume.

Second, the Pasuk tells us that the Omer is to be from the first harvest. וַהֲבֵאתֶ֥ם אֶת־עֹ֛מֶר רֵאשִׁ֥ית קְצִירְכֶ֖ם. By implication, this means that you are prohibited from harvesting anything prior to the cutting of the Omer. Once again, the harvesting of the Omer permits subsequent harvesting of all grain.

Finally, the Mishna expands on the topic of Chadash and explains that in order for the grain to be "freed" by the Korban Omer, it must have taken root prior to the bringing of the Korban. Otherwise, it will remain prohibited until after the following year's Korban if offered.

This exact Mishna is repeated in Challah 1:1 (with a slight change to the introduction leading some to suggest that that Mishna is a combinatin of our Mishna with an additional introductory phrase that, at one point, was the entirety of the Mishna in Challah).

* As of late, there are some who have questioned the identity of oats as on of the five grains.

**From every dough measuring at least 43 1/5 egg's in volume, you are required to set aside a portion of the dough for the Kohein.

הַחִטִּים וְהַשְּׂעֹרִים וְהַכֻּסְּמִין וְשִׁבֹּלֶת שׁוּעָל וְהַשִּׁיפוֹן

חַיָּבִין בַּחַלָּה, וּמִצְטָרְפִין זֶה עִם זֶה,
וַאֲסוּרִים בֶּחָדָשׁ מִלִּפְנֵי הַפֶּסַח,

וּמִלִּקְצֹר מִלִּפְנֵי הָעֹמֶר.
וְאִם הִשְׁרִישׁוּ קֹדֶם לָעֹמֶר, הָעֹמֶר מַתִּירָן.

וְאִם לָאו, אֲסוּרִים עַד שֶׁיָּבֹא עֹמֶר הַבָּא:

(7) Wheat, barley, spelt, oats and rye are subject to hallah. And they are reckoned together. They are forbidden [to be eaten] as new grain before the omer. And they may not be harvested before Pesah. If they had taken root before the omer, the omer permits them; And if not, they are forbidden until the next year's omer.

Introduction to Mishna 10:6

As we learned in Mishna 7, the bringing of the Korban Omer triggers the permissibility to both harvest and consume the new grain. Importantly, this was limited to the general population. For purposes of the Beis HaMikdash (i.e., for Korbonos), the new grain was only permitted to be used only after the "Shtei HaLechem," the two leavened loafs, were brought at the end of the counting of the Sefirah (i.e., Shavuous). Nevertheless, if the grain was used between the Omer and the Shtei HaLechem, the Korban was valid. If, however, the new grain was used prior to the Omer, than the Korban is invalid.

הָעֹמֶר הָיָה מַתִּיר בַּמְּדִינָה,

וּשְׁתֵּי הַלֶּחֶם בַּמִּקְדָּשׁ.
אֵין מְבִיאִין מְנָחוֹת וּבִכּוּרִים וּמִנְחַת בְּהֵמָה קֹדֶם לָעֹמֶר.

וְאִם הֵבִיא, פָּסוּל.

קֹדֶם לִשְׁתֵּי הַלֶּחֶם, לֹא יָבִיא. וְאִם הֵבִיא, כָּשֵׁר:

(6) The omer permits [the new grain] throughout the land, and the two loaves permit it in the Temple. One may not offer minhahs, first-fruits, or minhahs that accompany animal offerings, before the omer. And if one did so, it is invalid. Nor may one offer these before the two loaves. But if one did so it was valid.

Introduction to Mishna 10:5

As we learned in Mishna 7, it is prohibited to harvest any grains prior to the harvesting of the Omer. Once the Omer was harvested, however, you are allowed to harvest other grains. According to our Mishna, it seems that as soon as the Omer was offered the marketplace would be flooded with flour and grain from the new harvest. For this to happen, it meant that the farmers spent the night, after the Omer was cut, harvesting their fields and bringing the product to market. Our Mishna records a dispute between Rabi Meir and Rabi Yehuda whether this was appropriate behavior (i.e., should the merchants have waited some amount of additional time before offering their wares for sale).

According to Rabi Meir, the Chachomim extended the prohibition on harvesting until after the Omer was offered on the Mizbeach because they were afraid that if you allowed people to harvest the grain right way, they may inadvertently eat the grain prior the Omer's offering--which is biblically prohibited. Rabi Yehudah did not share that concern and even seemingly encouraged the grains' immediate appearance.

As noted, the offering of the Korban Omer was the triggering event permitting the consumption of the new grain. During the times of the Beis Hamikdash, for those living in and near Yerushalyim it was easy to ascertain when the Korban was brought, allowing the consumption of new grain. For those further away, they waited until Noon to eat the new grain because surely by then the Omer would have been brought.

In the absence of the Beis HaMikdash when are you allowed to eat the new grain? According to Rabban Yochanan Ben Zakkai, the grain is permitted starting at daybreak of the 16th of Nissan. However, if people grew accustomed to eating the new grain immediately, there was a concern that when the Beis HaMikdash would be rebuilt they may forget to wait until the Korban Omer was offered--resulting in a violation of a biblical prohibition. Therefore, he instituted a rule that you must wait until the eve of the 17th of Nissan (or 18th outside of Israel) before eating the new grain.

Rabi Yehudah, on the other hand, understood the words עַד־עֶ֙צֶם֙ הַיּ֣וֹם הַזֶּ֔ה עַ֚ד הֲבִ֣יאֲכֶ֔ם אֶת־קָרְבַּ֖ן as providing two trigger points. When there is a Beis HaMikdash, the bringing of the Korban frees the grain. However, in the absence of the Beis HaMikdash, you have to wait the entire day. As a practical matter, both Rabi Yehudah and Rabban Yochanan ben Zakkai require you to wait until the eve of the 17th of Nissan.

מִשֶּׁקָּרַב הָעֹמֶר,

יוֹצְאִין וּמוֹצְאִין שׁוּק יְרוּשָׁלַיִם שֶׁהוּא מָלֵא קֶמַח וְקָלִי, שֶׁלֹּא בִרְצוֹן חֲכָמִים, דִּבְרֵי רַבִּי מֵאִיר.

רַבִּי יְהוּדָה אוֹמֵר, בִּרְצוֹן חֲכָמִים הָיוּ עוֹשִׂים.
מִשֶּׁקָּרַב הָעֹמֶר, הֻתַּר הֶחָדָשׁ מִיָּד,

וְהָרְחוֹקִים מֻתָּרִים מֵחֲצוֹת הַיּוֹם וּלְהַלָּן.
מִשֶּׁחָרַב בֵּית הַמִּקְדָּשׁ,

הִתְקִין רַבָּן יוֹחָנָן בֶּן זַכַּאי, שֶׁיְּהֵא יוֹם הָנֵף כֻּלּוֹ אָסוּר.

אָמַר רַבִּי יְהוּדָה, וַהֲלֹא מִן הַתּוֹרָה הוּא אָסוּר, שֶׁנֶּאֱמַר (ויקרא כג), עַד עֶצֶם הַיּוֹם הַזֶּה.
מִפְּנֵי מָה הָרְחוֹקִים מֻתָּרִים מֵחֲצוֹת הַיּוֹם וּלְהַלָּן, מִפְּנֵי שֶׁהֵן יוֹדְעִין שֶׁאֵין בֵּית דִּין מִתְעַצְּלִין בּוֹ:

(5) After the omer was offered they used to go out and find the market of Jerusalem already full of flour and parched grain [of the new produce]; This was without the approval of the rabbis, the words of Rabbi Meir. Rabbi Judah says: it was with the approval of the rabbis. After the omer was offered the new grain was permitted immediately, but for those that lived far off it was permitted only after midday. After the Temple was destroyed Rabbi Yohanan ben Zakkai decreed that it should be forbidden throughout the day of the waving. Rabbi Judah said: is it not so forbidden by the law of the Torah, for it is said, “Until this very day?” Why was it permitted for those that lived far away from midday? Because they know that the court would not be negligent with it.

For an article summarizing the Takkanah of R' Yochanan ben Zakkai on Chodosh, see Prof. Eliezer E. Goldschmidt, Rabban Yohanan ben Zakkai's Regulation on New Grain [Hebrew], Hama'yan, Vol. 221, Nissan 5777 [57:3], pp10-19.

One view is that rather than extending a prohibition, in the absence of the korban Omer and it's inherent ability to permit Chadash, it was not clear how or when Chadash would become permitted in the new era. Rabban Yohanan ben Zakkai's core teaching was that the grain, in fact, becomes permitted immediately upon daybreak on the 16th of Nissan. He then instituted his decree to wait the extra day to both inculcate a sense of yearning for the Beis HaMikdash and to prevent a potenital violation of a biblical prohibition.

Introduction to Mishna 10:9

As noted above, no grain was to be harvested prior to the harvesting of the Korban Omer. The biblical prohibition, however, was limited to harvesting from fields whose grains were otherwise eligible to be used for the Korban Omer. (see Mishna 10:8). Our Mishna sets out a number of other exceptions. First, is grain growing among saplings. Since such grain is not eligible to be brought for the Korban Omer and if you let the grain grow it may damage the saplings, we allow you to remove it (and you do not have to worry that you will eat such grain prior to the Omer being brought). The second exception is when the harvest is being done for non-personal reasons, such as a Mitzvah. Our Mishna posits two cases of harvesting in aid of a Mitzvah. First, it is to clear an area where mourners can gather and people can make the appropriate blessing. Second, to clear an area so that more students may study Torah. Importantly, even when permitted to harvest, one must not do so in the regular way. He should not tie the stalks into bundles, but rather let them remain loose.

The Mishna then continues with a series of "best practices" one should try and undertake when bringing the Korban Omer. Importantly, if you cannot fulfill any (or all) of them the Korban may still be brought. The most intriguing one is that if the grain cannot be harvested by night, it may be done by day. This is seemingly in contradiction to the Mishna in Megillah 2:6 which counts the harvesting of the Omer among those Mitzvos to be done at night.

Finally, like with all public offerings, the Mishna tells us that the bringing of the Korban Omer (including the harvesting, processing and offering) pushes aside any prohibition Shabbos may impose.* Obviously the Boethusians would not agree.

*The Gemara records a dispute whether the reference to permissible actions on Shabbos includes even harvesting the Omer or whether it is limited to offering the Omer (but harvesting may not be done on Shabbos). The reason to exclude harvesting is since harvesting may be done by day (if need be) it remains prohibited to harvest on Shabbos--this presumes that the "day" also includes the day prior to the 16th (i.e., the 15th--or rather, the 14th of Nissan). Based on this, the Meforshim take exception to the RAMBAM's ruling that the Korban Omer may, if need be, harvested by day and that its harvesting also pushes aside Shabbos.

קוֹצְרִין מִפְּנֵי הַנְּטִיעוֹת,

מִפְּנֵי בֵית הָאֵבֶל,

מִפְּנֵי בִטּוּל בֵּית הַמִּדְרָשׁ.
לֹא יַעֲשֶׂה אוֹתָן כְּרִיכוֹת, אֲבָל מַנִּיחָן צְבָתִים.
מִצְוַת הָעֹמֶר

לָבֹא מִן הַקָּמָה. לֹא מָצָא, יָבִיא מִן הָעֳמָרִים.

מִצְוָתוֹ לָבֹא מִן הַלַּח. לֹא מָצָא, יָבִיא מִן הַיָּבֵשׁ.

מִצְוָתוֹ לִקְצֹר בַּלַּיְלָה. נִקְצַר בַּיּוֹם, כָּשֵׁר.

וְדוֹחֶה אֶת הַשַּׁבָּת:

(9) One may reap on account of the saplings or in order to make a house for mourners or in order not to interrupt the bet hamidrash. One may not bind them in bundles but one may leave them in small heaps. The mitzvah of the omer is that it should be brought from the standing grain. If this cannot be found he may bring it from the sheaves. The mitvah is that it should be brought from moist (fresh) grain. If this cannot be found he may bring it from dry grain. The mitzvah is that it should be reaped at night. If it was reaped at day it is valid. And it overrides the Shabbat.

חג שמח