(14) This day shall be to you one of remembrance: you shall celebrate it as a festival to ה' throughout the ages; you shall celebrate it as an institution for all time. (15) Seven days you shall eat matzot; on the very first day you shall remove leaven (seor) from your houses, for whoever eats chametz from the first day to the seventh day, that person shall be cut off from Israel. (16) You shall celebrate a sacred occasion on the first day, and a sacred occasion on the seventh day; no work at all shall be done on them; only what every person is to eat, that alone may be prepared for you. (17) You shall observe the [Feast of] Matzot, for on this very day I brought your ranks out of the land of Egypt; you shall observe this day throughout the ages as an institution for all time. (18) In the first month, from the fourteenth day of the month at evening, you shall eat matzah until the twenty-first day of the month at evening. (19) No leaven (seor) shall be found in your houses for seven days. For whoever eats what is leavened (machmetzet), that person—whether a stranger or a citizen of the country—shall be cut off from the community of Israel. (20) You shall eat nothing leavened (machmetzet); in all your settlements you shall eat matzot.
(ד) וְכִ֥י תַקְרִ֛ב קׇרְבַּ֥ן מִנְחָ֖ה מַאֲפֵ֣ה תַנּ֑וּר סֹ֣לֶת חַלּ֤וֹת מַצֹּת֙ בְּלוּלֹ֣ת בַּשֶּׁ֔מֶן וּרְקִיקֵ֥י מַצּ֖וֹת מְשֻׁחִ֥ים בַּשָּֽׁמֶן׃ {ס} (ה) וְאִם־מִנְחָ֥ה עַל־הַֽמַּחֲבַ֖ת קׇרְבָּנֶ֑ךָ סֹ֛לֶת בְּלוּלָ֥ה בַשֶּׁ֖מֶן מַצָּ֥ה תִהְיֶֽה׃ (ו) פָּת֤וֹת אֹתָהּ֙ פִּתִּ֔ים וְיָצַקְתָּ֥ עָלֶ֖יהָ שָׁ֑מֶן מִנְחָ֖ה הִֽוא׃ {ס} (ז) וְאִם־מִנְחַ֥ת מַרְחֶ֖שֶׁת קׇרְבָּנֶ֑ךָ סֹ֥לֶת בַּשֶּׁ֖מֶן תֵּעָשֶֽׂה׃ (ח) וְהֵבֵאתָ֣ אֶת־הַמִּנְחָ֗ה אֲשֶׁ֧ר יֵעָשֶׂ֛ה מֵאֵ֖לֶּה לַה' וְהִקְרִיבָהּ֙ אֶל־הַכֹּהֵ֔ן וְהִגִּישָׁ֖הּ אֶל־הַמִּזְבֵּֽחַ׃ (ט) וְהֵרִ֨ים הַכֹּהֵ֤ן מִן־הַמִּנְחָה֙ אֶת־אַזְכָּ֣רָתָ֔הּ וְהִקְטִ֖יר הַמִּזְבֵּ֑חָה אִשֵּׁ֛ה רֵ֥יחַ נִיחֹ֖חַ לַה'׃ (י) וְהַנּוֹתֶ֙רֶת֙ מִן־הַמִּנְחָ֔ה לְאַהֲרֹ֖ן וּלְבָנָ֑יו קֹ֥דֶשׁ קׇֽדָשִׁ֖ים מֵאִשֵּׁ֥י ה'׃ (יא) כׇּל־הַמִּנְחָ֗ה אֲשֶׁ֤ר תַּקְרִ֙יבוּ֙ לַה' לֹ֥א תֵעָשֶׂ֖ה חָמֵ֑ץ כִּ֤י כׇל־שְׂאֹר֙ וְכׇל־דְּבַ֔שׁ לֹֽא־תַקְטִ֧ירוּ מִמֶּ֛נּוּ אִשֶּׁ֖ה לַֽה'׃ (יב) קׇרְבַּ֥ן רֵאשִׁ֛ית תַּקְרִ֥יבוּ אֹתָ֖ם לַה' וְאֶל־הַמִּזְבֵּ֥חַ לֹא־יַעֲל֖וּ לְרֵ֥יחַ נִיחֹֽחַ׃
(4) When you present an offering of meal baked in the oven, [it shall be of] choice flour: unleavened cakes (challot matzot) with oil mixed in, or unleavened wafers (rekikei matzot) spread with oil. (5) If your offering is a meal offering on a griddle, it shall be matzah of choice flour with oil mixed in. (6) Break it into bits and pour oil on it; it is a meal offering. ...(11) No meal offering that you offer to shall be made chametz, for no leaven (seor) or honey may be turned into smoke as an offering by fire to ה'. (12) You may bring them to ה' as an offering of choice products; but they shall not be offered up on the altar for a pleasing odor.
כל המנחה אשר תקריבו לה' לא תעשה חמץ וטעם השאור והדבש יתכן שהוא כדברי הרב במורה הנבוכים (ג מו) אמר שמצא בספריהם שהמנהג היה לעובדי ע"ז להקריב כל מנחתם חמץ ולערב הדבש בכל קרבניהם ולכן אסרם לגבוה וכזה אמרו רבותינו (ספרי שופטים קמו) במצבה שהיתה נבחרת בימי האבות ואחר כך שנאה השם מפני שעשאוה חוק לע"ז כמו שאמר אשר שנא ה' אלקיך (דברים טז כב)
It is possible that the reason why we are forbidden to bring leaven and honey [upon the altar] is as the Rabbi [Moshe ben Maimon] states in the Guide for the Perplexed, where he says that he found it written in their books that the custom among those who engaged in foreign worship was to offer all their meal-offerings only in leavened form, and to season all their sacrifices with honey; therefore He forbade bringing them on His altar.
אִיכָּא דְאָמְרִי, הָא רַב הַמְנוּנָא מְצַלֵּי לַהּ. וְרַבִּי אָלֶכְּסַנְדְרִי בָּתַר דִּמְצַלֵּי אָמַר הָכִי: ״רִבּוֹן הָעוֹלָמִים, גָּלוּי וְיָדוּעַ לְפָנֶיךָ שֶׁרְצוֹנֵנוּ לַעֲשׂוֹת רְצוֹנֶךָ, וּמִי מְעַכֵּב? — שְׂאוֹר שֶׁבָּעִיסָּה וְשִׁעְבּוּד מַלְכֻיוֹת. יְהִי רָצוֹן מִלְּפָנֶיךָ שֶׁתַּצִּילֵנוּ מִיָּדָם, וְנָשׁוּב לַעֲשׂוֹת חוּקֵּי רְצוֹנְךָ בְּלֵבָב שָׁלֵם״.
Some say that this was the prayer that Rav Hamnuna would recite, and that after Rabbi Alexandri prayed, he would say the following: Master of the Universe, it is revealed and known before You that our will is to perform Your will, and what prevents us?
the yeast in the dough, and the subjugation to the kingdoms.
May it be Your will that You will deliver us from their hands, so that we may return to perform the edicts of Your will with a perfect heart.
ולא יאכל חמץ. כדי להשריש הזכירה בלב ע״י איזה פעולה המראה ומזכיר זה הענין צויתי שלא יאכל חמץ. דמצה אין בה יתרון ע״י תחבולות ידי האדם להעלות העיסה יותר מהקמח והמים שנבראים ממנו ית׳. משא״כ חמץ שולט בם תחבולות האדם להעלות העיסה ע״י שאור מש״ה הוא אות שקיום ישראל הוא רק ברוח ה׳. ואפילו בעת שהיינו בא״י ומנהיגים מלוכה ומלחמת תנופה כדרך תחבולות האדם. כל התחבולות לא היו אלא כדי שיהא נראה כמעשה טבע לפי שאין הדור ראוי לנס נגלה אבל העיקר היה תלוי אם ה׳ היה יוצא בצבאותינו בהשגחה פרטית. וכש״כ בעת שישראל מפוזרים בעמים ידוע אשר אך השגחת ה׳ ורוח היהודית שבהם מאחדם ומקיימם בעולם:
"LEAVEN MAY NOT BE EATEN (on Passover) ... matza takes no advantage of the human technological ingenuity and creativity which allows man to raise the dough more than simple flour and water which are created by God. Chametz is the epitome of human involvement in nature. Thus, non-leaven is the symbol of the survival and ongoing existence of the Jewish People as they survive solely through the spirit of God."
יא) שם הגה. והמנהג לשורפו. היינו ור"ל כי ע"י שריפת החמץ רומזת אל בחי' הקלי' שיתבערו מן העולם בסוד "ואת רוח הטומאה אעביר מן הארץ" ותתקרב קץ הגאולה ולכן נהגו לשרפו.
The custom is to burn it: Meaning to say, by burning the Chametz, it alludes towards the peels/Kelipot that need to be removed from the world, as is the Kabbalistic meaning of the verse "and the spirit of impurity will be removed from the land" (Zachariah 13:20) and bring the redemption. Which is why we have the custom to burn it.
One final approach comes from a contemporary scholar - Rav Yoel Bin Nun. He notes that there are occasions when we DO bring leaven to the Temple (although it is not offered up on the altar itself). On Shavuot - Pentecost - we bring two loaves of bread to the Temple (Vayikra 23:17). In the thanksgiving offering (a variation of the peace offering - shelamim), three types of loaves are brought to the Temple: unleavened wafers - like our matzot; unleavened loaves - like pita; and leavened loaves - like our bread.
What is the symbolism that leaven and unleaven represent in the Temple? Leaven represents fulfillment, a process which has gone its due course. The ultimate and supreme form of flour and water is a leavened loaf. Unleaven, on the other hand, is "not yet" what it aspires to be; it figuratively represents the beginning of a yet-unfulfilled process. It is presently immature and unripe. It is in the early stages of a journey.
The altar of God is not a place for leaven. Before God, we are all rough around the edges. We all have a way to go in reaching our own personal destiny. We have faults, room for improvement. We cannot express ourselves before God represented by the symbol of leaven, for we are at the beginning of a journey. We are the unleavened, still traveling on the tortuous road that is human and religious betterment.
So when do we bring leaven to the Temple?
Shavuot is the Festival of Weeks. It is also the festival designated as the time to bring first fruits from the new crop in the Land of Israel to the Temple. Shavuot is linked to Pesach by the Omer. We count seven cycles of seven days from Pesach and then we celebrate Shavuot. Pesach is the start of a process; Shavuot is the end. On Pesach, we remove all leaven and eat only unleavened bread. On Shavuot, we bring loaves of leaven. It is a question of a process.
On Pesach we had our freedom. One might revel in the euphoria of freedom and imagine that this is it. We have reached our goal, we have achieved independence. In response, God tells us to eat only matza - unleavened, unfulfilled bread - for seven days. Pesach begins a process. It is a cause for celebration, but it is only the start. The goal comes seven weeks later in a festival which celebrates two things. First, it celebrates our spiritual challenge. It is the festival of the giving of the Torah. The Torah embodies our challenge, our goal and our destiny. Second, it is the festival of the Land of Israel. On Shavuot, we bring the first fruits and stress the idea that the goal is creating "a kingdom of priests and a holy nation" - a people in the land of God living the moral law of God.
(https://www.etzion.org.il/en/holidays/pesach/symbolism-chametz)