וּשְׂמַחְתֶּם לִפְנֵי ה׳ אֱלֹהֵיכֶם. אֵין שִׂמְחָתָם לִפְנֵי ה׳ כִּי אִם בִּזְמַן שֶׁהֵם בַּאֲגֻדָּה אַחַת, וּבִפְרָט שֶׁהַשִּׂמְחָה דַּוְקָא בְּחַג זֶה, לְפִי שֶׁהוּא זְמַן אֲסִיפָה אֲשֶׁר מִדֶּרֶךְ הָעוֹלָם לִשְׂמֹחַ בָּהּ בְּיוֹתֵר. עַל כֵּן הִזְהִירָם שֶׁתִּהְיֶה הַשִּׂמְחָה לִפְנֵי ה׳ דַּוְקָא, לֹא כְּשִׂמְחַת הָרֵקִים אֲשֶׁר כָּל מְזִמּוֹתָם הָרֹג בָּקָר וְשָׁחֹט צֹאן (ישעיה כב יג), הַשּׁוֹתִים בְּמִזְרְקֵי יַיִן, וּמַרְבִּים מַחֲלֹקֶת בְּיִשְׂרָאֵל, וּבְשִׂמְחָה זוֹ הֶחֱרִיבוּ שְׁנֵי בָּתֵּי מִקְדָּשִׁים וְגָלוּ בְּרֹאשׁ גּוֹלִים, כְּמוֹ שֶׁנֶּאֱמַר (ישעיה נה יב): ״כִּי בְּשִׂמְחָה תֵּצֵאוּ״. כְּאָמְרוּ רז״ל (קידושין פא.): סְקָבָא דְּשַׁתָּא רִגְלָא, כִּי בַּעֲבוּר שֶׁהָיוּ שְׂמֵחִים שֶׁלֹּא לְשֵׁם שָׁמַיִם סִבְּבוּ כָּל חֳלִי וְכָל מַכָּה כְּמַעֲשֵׂה הָאֶתְרוֹג שֶׁזָּרְקוּ בְּיַנַּאי הַמֶּלֶךְ (עיין סוכה מח:). וְעַל שִׂמְחָה זוֹ אָמַר מַה זּוֹ עֹשָׂה, הֲלֹא עַל יָדָהּ תֵּצְאוּ בְּרֹאשׁ גּוֹלִים. אָמְנָם ״בְּשָׁלוֹם״, כְּשֶׁיִּהְיוּ בַּאֲגֻדָּה אַחַת וְשָׁלוֹם בֵּינֵיהֶם – ״תּוּבָלוּן״ אֶל הָאָרֶץ, ״הֶהָרִים וְהַגְּבָעוֹת״, הֵמָּה רָאשֵׁי הַמַּעֲלָה אֲשֶׁר גֹּבַהּ לָהֶם וְיִרְאָה לָהֶם (יחזקאל א יח), ״יִפְצְחוּ לִפְנֵיכֶם רִנָּה״, כִּי יִהְיוּ קוֹדְמִים לְכָל דָּבָר שֶׁבִּקְדֻשָּׁה כְּדִינָם, וְלֹא יִהְיוּ הַנְּעָרִים דּוֹחֲפִין אֶת הַזְּקֵנִים כְּמַעֲשֵׂה הַמְרַגְּלִים. ״וְכָל עֲצֵי הַשָּׂדֶה יִמְחֲאוּ כָף״, הֵמָּה כָּל אַרְבַּע כִּתּוֹת הָרְמוּזִים בְּאַרְבַּע מִינִים אֵלּוּ הַבָּאִים מֵעֲצֵי הַשָּׂדֶה, יִמְחֲאוּ כָף לִשְׂמֹחַ לִפְנֵי ה׳. וְכֵן בְּמָקוֹם אַחֵר (ויק״ר ל ד) דָּרְשׁוּ פָּסוּק זֶה ״אָז יְרַנְּנוּ כָּל עֲצֵי יָעַר״ (תהלים צו יב), עַל אַרְבָּעָה מִינִים אֵלּוּ, וְרָמַז בְּמִלַּת אָז א׳ ז׳, שֶׁהַלּוּלָב נִטָּל בַּמִּקְדָּשׁ כָּל שִׁבְעָה וּבַגְּבוּלִין יוֹם אֶחָד.
And you shall rejoice before the Lord your God. There is no rejoicing before the Lord except when they are in one group, especially since the rejoicing is specifically on this festival because it is the time of gathering, which is naturally a time of increased joy. Therefore, He warned them that the rejoicing should be specifically before the Lord, not like the rejoicing of the empty ones whose every scheme is killing cattle and slaughtering sheep (Isaiah 22:13), who drink from wine bowls and increase division in Israel. With this kind of rejoicing they destroyed both Temples and went into exile at the head of exiles, as it is written For with joy you shall go out (Isaiah 55:12). As our Sages said (Kiddushin 81a), “The most dangerous time of the year is the festival,” because when they rejoiced not for the sake of Heaven, they brought about all manner of illness and affliction, like the incident of the etrog that was thrown at King Yannai (see Sukkah 48b). Concerning this kind of rejoicing, He said, “What is this that you have done? Is it not because of this that you shall go out at the head of exiles”? However, in peace — when they are united as one group with peace between them — you will be led forth. To the land, the mountains and hills — these are the leaders of high rank who have height and are respected (Ezekiel 1:18) — they will break forth before you in singing. For they will be first in all matters of holiness as is proper, and the youth will not push aside the elders as happened with the spies. And all the trees of the field will clap their hands — these are the four groups symbolized by these four species that come from the trees of the field. They will clap their hands to rejoice before the Lord. Similarly, in another place (Vayikra Rabbah 30:4), they interpreted the verse Then all the trees of the forest will sing for joy (Psalms 96:12) as referring to these four species, and it hinted at this in the word then [az] — Aleph [has a numerical value of] one, Zayin [has a numerical value of] seven — that the lulav is taken in the Temple all seven [days] and in the outlying areas for one day.