The Chinukh presents the mitzvah of lulav and expands on its educational and spiritual purpose. He explains how the act of taking the species shapes joy, gratitude, and awareness of God.
וּכְמוֹ כֵן מִצְוַת הַלּוּלָב עִם שְׁלֹשֶׁת מִינָיו מִזֶּה הַשֹּׁרֶשׁ הִיא, לְפִי שֶׁיְּמֵי הֶחָג הֵם יְמֵי שִׂמְחָה גְּדוֹלָה לְיִשְׂרָאֵל כִּי הוּא עֵת אֲסִיפַת הַתְּבוּאוֹת וּפֵרוֹת הָאִילָן לַבַּיִת, וְאָז יִשְׂמְחוּ בְּנֵי אָדָם שִׂמְחָה רַבָּה, וּמִפְּנֵי כֵן נִקְרָא חַג הָאָסִיף. וְצִוָּה הָאֵל לְעַמּוֹ לַעֲשׂוֹת לְפָנָיו חַג בְּאוֹתָהּ הָעֵת לְזַכּוֹתָם לִהְיוֹת עִקַּר הַשִּׂמְחָה לִשְׁמוֹ יִתְבָּרַךְ, וּבִהְיוֹת הַשִּׂמְחָה מוֹשֶׁכֶת הַחֹמֶר הַרְבֵּה וּמְשַׁכַּחַת מִמֶּנּוּ יִרְאַת אֱלֹהִים, בָּעֵת הַהִיא צִוָּנוּ הַשֵּׁם לָקַחַת בֵּין יָדֵינוּ דְּבָרִים הַמַּזְכִּירִים אוֹתָנוּ כִּי כָּל שִׂמְחַת לִבֵּנוּ לִשְׁמוֹ וְלִכְבוֹדוֹ, וְהָיָה מֵרְצוֹנוֹ לִהְיוֹת הַמַּזְכִּיר מִין הַמְשַׂמֵּחַ כְּמוֹ שֶׁהָעֵת עֵת שִׂמְחָה, כִּי צֶדֶק כָּל אִמְרֵי פִיו, וְיָדוּעַ מִצַּד הַטֶּבַע כִּי אַרְבַּעַת הַמִּינִין כֻּלָּם מְשַׂמְּחֵי לֵב רוֹאֵיהֶם. וְעוֹד יֵשׁ בְּאַרְבָּעָה מִינִין אֵלּוּ עִנְיָן אַחֵר, שֶׁהֵם דּוֹמִים לְאֵבָרִים שֶׁבָּאָדָם הַיְּקָרִים (עי' מדרש רבה ויקרא פ' ל' ומדרש תנחומא אמור אות יט). שֶׁהָאֶתְרוֹג דּוֹמֶה לַלֵּב, שֶׁהוּא מִשְׁכַּן הַשֵּׂכֶל, לִרְמֹז שֶׁיַּעֲבֹד בּוֹרְאוֹ בְּשִׂכְלוֹ, וְהַלּוּלָב דּוֹמֶה לַשִּׁדְרָה שֶׁהִיא הָעִקָּר שֶׁבָּאָדָם לִרְמֹז שֶׁיַּיְשִׁיר כָּל גּוּפוֹ לַעֲבוֹדָתוֹ בָּרוּךְ הוּא, וְהַהֲדַס דּוֹמֶה לָעֵינַיִם, לִרְמֹז שֶׁלֹּא יָתוּר אַחַר עֵינָיו בְּיוֹם שִׂמְחַת לִבּוֹ, וְהָעֲרָבָה דּוֹמָה לַשְּׂפָתַיִם, שֶׁבָּהֶן יִגְמֹר הָאָדָם כָּל מַעֲשֵׂהוּ בְּדִבּוּר, לִרְמֹז שֶׁיָּשִׂים רֶסֶן בְּפִיו וִיכַוֵּן דְּבָרָיו וְיִירָא מֵהַשֵּׁם יִתְבָּרַךְ אַף בְּעֵת הַשִּׂמְחָה. וְטַעַם שֶׁאֵינוֹ נוֹהֵג בַּמְּדִינָה אֶלָּא יוֹם אֶחָד, לְפִי שֶׁיָּדוּעַ, כִּי עִקַּר הַשִּׂמְחָה, בְּיוֹם רִאשׁוֹן הוּא, וְאִם תִּשְׁאַל שְׁמִינִי עֲצֶרֶת שֶׁיֵּשׁ בּוֹ שִׂמְחָה גְּדוֹלָה לְיִשְׂרָאֵל, לָמָּה לֹא הָיָה נִטַּל בּוֹ. הַתְּשׁוּבָה, כִּי יוֹם שְׁמִינִי עֲצֶרֶת כֻּלּוֹ לַשֵּׁם יִתְבָּרַךְ וּכְמוֹ שֶׁאָמְרוּ זִכְרוֹנָם לִבְרָכָה (במדבר ובה פ' כא אות כב ובמדרש הגדול שמות כט לו) מָשָׁל לְמֶלֶךְ שֶׁעָשָׂה סְעוּדָה וכו'. כִּדְאִיתָא בַּמִּדְרָשׁ, וּלְבַסּוֹף אָמַר לָהֶם עַכְּבוּ עִמִּי יוֹם אֶחָד, שֶׁקָּשָׁה עָלַי פְּרֵדַתְכֶם, וּלְפִיכָךְ נִקְרָא עֲצֶרֶת, וְאִם כֵּן אֵין צָרִיךְ זִכָּרוֹן אַחֵר. וְחַג הַפֶּסַח אֵין צָרִיךְ הַזְכָּרָה בַּלּוּלָב, שֶׁהֲרֵי מַצָּה וּמָרוֹר וְגוּפוֹ שֶׁל פֶּסַח בֵּין יָדָיו, וְעוֹד שֶׁאֵינוֹ זְמַן שִׂמְחָה כְּמוֹ חַג הָאָסִיף, וְחַג הַשָּׁבוּעוֹת גַּם כֵּן אֵין צָרִיךְ הַזְכָּרָה אַחֶרֶת, כִּי עִקַּר הָרֶגֶל אֵינוֹ אֶלָּא מִצַּד מַתַּן תּוֹרָתֵנוּ, וְהִיא זִכְרוֹנֵנוּ הַגָּדוֹל לְיַשֵּׁר כָּל אָרְחוֹתֵינוּ. זֶהוּ הַנִּרְאֶה לִי בְּעִנְיָנִים אֵלּוּ עַל צַד הַפְּשָׁט, וְהֶאֱמַנְתִּי כִּי יֵשׁ אֶל הַמְקֻבָּלִים סוֹדוֹת נִפְלָאִים בְּמִצְוַת הַלּוּלָב וּשְׁלֹשֶׁת הַמִּינִים.
And so too from this root is the commandment of the lulav with its three [other plants]. As the days of the holiday are days of great joy for Israel, since it is the time of the gathering of the grain and the fruit of the tree into the home; and all men rejoice a great rejoicing. And for this reason it is called the holiday of the gathering (HaAsif). And God commanded His people to make a holiday in front of Him at that time to give them merit, such that the main joy will be for His sake, may He be blessed. And since joy greatly elicits the physical and makes one forget the fear of God, God commanded us at that time to take in our hands things that remind us that all the joy of our heart is for His sake and His honor. And it was from His will that the reminder be from that which brings joy, just as the time is a time of joy — as all of the words of His mouth are just. And it is well-known that it is the nature of all of these four species to gladden the heart of those that see them. And there is also another matter with these four things — that they are similar to precious limbs in a man (see Vayikra Rabbah 30:14; Midrash Tanchuma, Emor 19): As the citron is similar to the heart, which is the dwelling place of the intellect, to hint that he should serve His Creator with his intellect; the lulav is similar to the backbone, which is the essence of a person, to hint that he should straighten himself completely for His service, blessed be He; the myrtle [leaves are] similar to the eyes, to hint that he should not stray after his eyes “on the day of the rejoicing of his heart”; and the willow [leaves are] similar to the lips, with which a man completes all of his acts of speech, to hint that he should put a muzzle to his mouth, calibrate his words and fear God, may He be blessed, even at a time of joy. And the reason that it is only practiced one day in the country (outside of the Temple) is well-known — since the main joy is on the first day. And if you should ask, “Why would one not take it on Shemini Atseret, which has great joy on it for Israel” — the answer is that the day of Shemini Atseret is completely for God, may He be blessed. And [it is] as they, may their memory be blessed, said (Bamidbar Rabbah 21:22; Midrash HaGadol, Shemot 29:36), “A parable of a king who made a feast, etc.,” as it is [found] in the Midrash. And at the end, He said to them, “Remain with Me one day, as your departure is difficult for Me.” And therefore, it is called atseret (a stopping). And if so, there is no need for any other reminder. And the holiday of Pesach does not require another reminder with the lulav, as behold the matsah and marror and the body of the Pesach sacrifice are between his hands; and further since it is not a time of joy as [much as is] the holiday of the gathering. And the holiday of Shavuot also does not require another reminder, since the essence of [that] festival is only from the angle of the giving of our Torah — and that is the great reminder to straighten our ways. And this is what appears to me in these matters from the side of the simple understanding. And I have come to believe that the kabbalists (mystics) have wonderful secrets about the commandment of the lulav and the three [other plants].