שֶׁלֹּא יִמָּצֵא חָמֵץ בִּרְשׁוּתֵנוּ בְּפֶסַח – שֶׁלֹּא יִמָּצֵא חָמֵץ בִּרְשׁוּתֵנוּ כָּל יְמֵי הַפֶּסַח, שֶׁנֶּאֱמַר (שמות יב יט) שִׁבְעַת יָמִים שְׂאֹר לֹא יִמָּצֵא בְּבָתֵּיכֶם. וּבֵאֲרוּ חֲכָמֵינוּ זִכְרוֹנָם לִבְרָכָה (פסחים ה, ב) לָאו דַּוְקָא בֵּיתוֹ, אֶלָּא כָּל שֶׁבִּרְשׁוּתוֹ. וְלָאו דַּוְקָא שְׂאוֹר שֶׁהוּא מְחַמֵּץ, דְּהוּא הַדִּין לְחָמֵץ. דִּשְׂאוֹר וְחָמֵץ חַד הוּא לְעִנְיַן אִסּוּרוֹ. (ביצה ז, ב) That chamets not be found in our possession on Pesach: That chamets not be found in our possession on all the days of Pesach, as it is stated (Exodus 12:19), “Seven days leaven is not to be found in your homes.” And our Sages, may their memory be blessed, elucidated (Pesachim 5b) that it is not specifically one’s home, but rather anything that is in his possession; and not specifically leaven which makes rise, but the same is true of [any grain product] that has risen — as leaven and leavened grain products are one [and the same] concerning the matter of its prohibition (Beitzah 7b).
מִשָּׁרְשֵׁי הַמִּצְוָה, כְּדֵי שֶׁנִּזְכֹּר לְעוֹלָם הַנִּסִּים שֶׁנַּעֲשׂוּ לָנוּ בִּיצִיאַת מִצְרַיִם, כְּמוֹ שֶׁכָּתוּב בְּשֵׂה הַפֶּסַח. וְנִזְכֹּר מָה שֶׁאֵרַע לָנוּ בְּעִנְיָן זֶה, שֶׁמִּתּוֹךְ חֶפְזוֹן הַיְּצִיאָה אָפִינוּ הָעִסָּה מַצָּה, כִּי לֹא יָכְלוּ לְהִתְמַהְמֵהַּ עַד שֶׁיַּחְמִיץ, כְּמוֹ שֶׁכָּתוּב (שמות יב לט) וַיֹּאפוּ אֶת הַבָּצֵק וְגוֹ'. It is from the roots of the commandment [that it is] so that we should always remember the miracles that were done for us in the exodus from Egypt, as is written with the lamb of the Pesach sacrifice (Sefer HaChinukh 5). And we should remember that which occurred to us with this matter — that as a result of the haste of the exodus, we baked the dough [into] matsah. As they could not wait until it rose, as it is written (Exodus 12:39), “And they baked the dough, etc.”
דִּינֵי הַמִּצְוָה, כְּגוֹן אִם הִפְקִיד חֲמֵצוֹ בְּיַד אֲחֵרִים מָה דִּינוֹ אוֹ אֲחֵרִים בְּיָדוֹ, וְכֵן חָמֵץ הֶקְדֵּשׁ בְּיָדוֹ, אוֹ שֶׁל גּוֹי בְּאַחְרָיוּת וְשֶׁלֹּא בְּאַחְרָיוּת, וְדִין עַכּוּ"ם אַלָּם שֶׁהִפְקִיד לוֹ חָמֵץ, וְדִין תַּעֲרֹבֶת חָמֵץ אִם עוֹבְרִים עָלָיו. וְהַפַּת שֶׁעִפְּשָׁה מָה דִּינָהּ, (שם מה, ב) וְיֶתֶר פְּרָטֶיהָ, מְבֹאָרִים בְּפֶסַח רִאשׁוֹן (אורח חיים ת"מ תמ"א תמ"ב). The laws of this commandment — for example if he deposits his chamets in the hand of others or [that of] others [is deposited] into his hand, and also chamets that is sacred property that is in his hand or that of a gentile, with responsibility or without responsibility, and the law of a violent [gentile] that deposited chamets with him; the law of whether one transgresses for a mixture that includes chamets; what is the law of bread that has rotted (Pesachim 45b); and the rest of its details — are elucidated in [the] first [section of] Pesach[im]. (See Tur, Orach Chaim 440-442.)
וְנוֹהֶגֶת בִּזְכָרִים וּנְקֵבוֹת בְּכָל מָקוֹם וּבְכָל זְמַן. וְהָעוֹבֵר עָלֶיהָ וְנִמְצָא חָמֵץ בִּרְשׁוּתוֹ בְּמֵזִיד, עָבַר עַל שְׁנֵי לָאוִין מִשּׁוּם בַּל יֵרָאֶה וּבַל יִמָּצֵא, וְלוֹקֶה כָּל זְמַן שֶׁעָשָׂה בּוֹ מַעֲשֶׂה, כְּגוֹן שֶׁחִמֵּץ עִסָּה וְהִנִּיחָהּ בְּבֵיתוֹ, אוֹ שֶׁלָּקַח חָמֵץ וְהִצְנִיעוֹ בְּבֵיתוֹ. אֲבָל אִם לֹא עָשָׂה בּוֹ שׁוּם מַעֲשֶׂה, אֶלָּא שֶׁנִּשְׁאַר בַּבַּיִת מִקֹּדֶם הַפֶּסַח, אֵין לוֹקֶה עָלָיו, שֶׁהֲלָכָה הִיא (רמב"ם חו"מ א, ג), לָאו שֶׁאֵין בּוֹ מַעֲשֶׂה אֵין לוֹקִין עָלָיו, כְּמוֹ שֶׁאָמַרְנוּ. And [it] is practiced by males and females in every place and at all times. And one who transgresses it and chamets is volitionally found in his possession violates two negative commandments, on account of “that it not be seen and it not be found.” And he is lashed anytime he does an act with it — for example [if] he had dough rise and left it in his home, or he purchased chamets and stored it in his home. But if he did not do any act, but it [just] remained at home from before Pesach, he is not lashed (Mishneh Torah, Laws of Leavened and Unleavened Bread 1:3). As it is the law that we do not administer lashes for a negative commandment that does not have an act [involved] with it, as we have said.