The Gemara establishes that the prohibition of chametz and the obligation of matzah apply specifically to the five species of grain: wheat, barley, spelt, rye, and oats. Corn (maize) is not among them, providing the foundational basis for why corn is not biblically prohibited.
מַתְנִי׳ אֵלּוּ דְּבָרִים שֶׁאָדָם יוֹצֵא בָּהֶן יְדֵי חוֹבָתוֹ בַּפֶּסַח: בְּחִטִּים, בִּשְׂעוֹרִים, בְּכוּסְּמִין וּבְשִׁיפוֹן וּבְשִׁיבּוֹלֶת שׁוּעָל. וְיוֹצְאִין בִּדְמַאי וּבְמַעֲשֵׂר רִאשׁוֹן שֶׁנִּטְּלָה תְּרוּמָתוֹ, וּבְמַעֲשֵׂר שֵׁנִי וְהֶקְדֵּשׁ שֶׁנִּפְדּוּ. וְהַכֹּהֲנִים בַּחַלָּה וּבַתְּרוּמָה. גְּמָ׳ תָּנָא: כּוּסְּמִין — מִין חִיטִּין, שִׁיבּוֹלֶת שׁוּעָל וְשִׁיפוֹן — מִין שְׂעוֹרִין. כּוּסְּמִין — גּוּלְבָּא, שִׁיפוֹן — דִּישְׁרָא, שִׁיבּוֹלֶת שׁוּעָל — שֻׁבְילֵי תַעֲלָא. הָנֵי אִין, אוֹרֶז וְדוֹחַן — לָא. מְנָהָנֵי מִילֵּי? אָמַר רַבִּי שִׁמְעוֹן בֶּן לָקִישׁ, וְכֵן תָּנָא דְּבֵי רַבִּי יִשְׁמָעֵאל, וְכֵן תָּנָא דְּבֵי רַבִּי אֱלִיעֶזֶר בֶּן יַעֲקֹב: אָמַר קְרָא ״לֹא תֹאכַל עָלָיו חָמֵץ שִׁבְעַת יָמִים תֹּאכַל עָלָיו מַצּוֹת״. דְּבָרִים הַבָּאִים לִידֵי חִימּוּץ — אָדָם יוֹצֵא בָּהֶן יְדֵי חוֹבָתוֹ בְּמַצָּה, יָצְאוּ אֵלּוּ שֶׁאֵין בָּאִין לִידֵי חִימּוּץ, אֶלָּא לִידֵי סִירְחוֹן.
MISHNA: These are the types of grain with which a person fulfills his obligation to eat matza on the first night of Passover: With wheat, with barley, with spelt [kusmin], with rye [shifon], and with oats [shibbolet shu’al]. And one fulfills his obligation by eating not only matza made from properly tithed grains, but even with matza made from doubtfully tithed produce, and matza made with first tithe from which its teruma was already taken, or second tithe and consecrated food that were redeemed. And priests may eat matza prepared from ḥalla, the portion of dough that is given to priests, or with teruma, as priests are permitted to eat these portions. GEMARA: The Gemara identifies the species mentioned in the mishna. One of the Sages taught in the Tosefta: Spelt is a type of wheat, while oats [shibbolet shu’al] and rye [shifon] are a type of barley. The Gemara translates the lesser-known species into the vernacular Aramaic: Spelt is called gulba; rye is dishra; and oats are shevilei ta’ala. The Gemara infers: These species, yes, they may be used for matza; however, rice [orez] and millet [doḥan], no, they may not be used. The Gemara asks: From where are these matters, that matza cannot be prepared from rice or millet, derived? Rabbi Shimon ben Lakish said, and likewise a Sage of the school of Rabbi Yishmael taught, and likewise a Sage of the school of Rabbi Eliezer ben Ya’akov taught that the verse states: “You shall eat no leavened bread with it; seven days you shall eat with it matza, the bread of affliction” (Deuteronomy 16:3). This verse indicates that only with substances which will come to a state of leavening, a person fulfills his obligation to eat matza with them, provided he prevents them from becoming leavened. This excludes these foods, i.e., rice, millet, and similar grains, which, even if flour is prepared from them and water is added to their flour, do not come to a state of leavening but to a state of decay [siraḥon].