(Devarim 16:9) "Seven weeks shall you count for yourself": I might think that beth-din (is being exhorted to do the counting); it is, therefore, written (Vayikra 22:15) "And you shall count for yourselves" — each individual (is exhorted to do the counting).
I might think that he could harvest and bring (the omer), and (count) whenever he wished; it is, therefore, written (Vayikra, Ibid.) "And you shall count for yourselves from the morrow of the Sabbath" (i.e., from the morrow of the first day of Pesach).
I might think that he could count and bring (the omer), and harvest whenever he wished; it is, therefore, written "when the sickle begins (to harvest) the standing corn." I might think that he could harvest at night and count at night and bring (the omer) at night; it is, therefore, written (Ibid.) "from the day that you bring (the omer)."
I might think that he could harvest in the daytime and count in the daytime and bring (the omer) in the daytime; it is, therefore, written (Ibid.) "Seven complete Sabbaths shall they be," (the counting until Shavuoth not being complete if the first day is counted in the daytime.) When are they complete? When you begin in the evening.
I might think that he could harvest at night and count at night and bring (the omer) at night; it is, therefore, written (Ibid.) "from the day that you bring (the omer)."
(דברים טז ט) שִׁבְעָה שָׁבֻעוֹת תִּסְפָּר לָךְ – בְּבֵית דִּין. מִנַּיִן לְכָל אֶחָד וְאֶחָד? תַּלְמוּד לוֹמַר (ויקרא כג טו): ״וּסְפַרְתֶּם לָכֶם מִמָּחֳרַת הַשַּׁבָּת״ – כָּל אֶחָד וְאֶחָד.
(Devarim 16:9) "Seven weeks shall you count for yourself": I might think that beth-din (is being exhorted to do the counting); it is, therefore, written (Vayikra 22:15) "And you shall count for yourselves" — each individual (is exhorted to do the counting).
מֵהָחֵל חֶרְמֵשׁ בַּקָּמָה, מִשֶּׁתַּתְחִיל חֶרְמֵשׁ בַּקָּמָה,
"From the beginning of the sickle": (The intent is) when the sickle begins, and that its harvesting be only with the sickle.
שֶׁיְּהֵא הַכֹּל בַּקָּמָה, שֶׁיְּהֵא תְּחִלָּה לְכָל הַנִּקְצָרִים; שֶׁלֹּא תְּהֵא קְצִירָתוֹ אֶלָּא בְּחֶרְמֵשׁ.
"in the standing corn": that all be standing (i.e., that nothing has yet been harvested); that it be the first of all that is harvested.
יָכוֹל יִקְצוֹר וְיָבִיא, וְיִסְפּוֹר כָּל זְמַן שֶׁיִּרְצֶה? תַּלְמוּד לוֹמַר: מֵהָחֵל חֶרְמֵשׁ בַּקָּמָה תָּחֵל לִסְפֹּר.
I might think that he could harvest and bring (the omer), and (count) whenever he wished; it is, therefore, written (Vayikra, Ibid.) "And you shall count for yourselves from the morrow of the Sabbath" (i.e., from the morrow of the first day of Pesach).
יָכוֹל יִקְצוֹר וְיִסְפּוֹר, וְיָבִיא כָּל זְמַן שֶׁיִּרְצֶה? תַּלְמוּד לוֹמַר (ויקרא כג טו): ״מִיּוֹם הֲבִיאֲכֶם תִּסְפְּרוּ״.
I might think that he could count and bring (the omer), and harvest whenever he wished; it is, therefore, written "when the sickle begins (to harvest) the standing corn." I might think that he could harvest at night and count at night and bring (the omer) at night; it is, therefore, written (Ibid.) "from the day that you bring (the omer)."
יָכוֹל יִקְצוֹר בַּיּוֹם וְיִסְפּוֹר בַּיּוֹם וְיָבִיא בַּיּוֹם? תַּלְמוּד לוֹמַר (ויקרא כג טו): ״שֶׁבַע שַׁבָּתוֹת תְּמִימוֹת תִּהְיֶינָה״. אֵימָתַי הֵן תְּמִימוֹת? מִשֶּׁאַתָּה מַתְחִיל מִבָּעֶרֶב.
I might think that he could harvest in the daytime and count in the daytime and bring (the omer) in the daytime; it is, therefore, written (Ibid.) "Seven complete Sabbaths shall they be," (the counting until Shavuoth not being complete if the first day is counted in the daytime.) When are they complete? When you begin in the evening.
יָכוֹל יִקְצוֹר בַּלַּיְלָה וְיִסְפּוֹר בַּלַּיְלָה וְיָבִיא בַּלַּיְלָה? תַּלְמוּד לוֹמַר (ויקרא כג טו): ״מִיּוֹם הֲבִיאֲכֶם תִּסְפְּרוּ״, אֵין הֲבָאָה אֶלָּא בַּיּוֹם.
I might think that he could harvest at night and count at night and bring (the omer) at night; it is, therefore, written (Ibid.) "from the day that you bring (the omer)."
הָא כֵּיצַד? קְצִירָה וּסְפִירָה בַּלַּיְלָה, וַהֲבָאָה בַּיּוֹם.
What, then, is the procedure? Harvesting, counting at night, and bringing (the omer) in the daytime.