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There are six Torah commands [counted as part of the 613 Mitzvos] which involve the Chametz prohibition. Five negative commands, and one positive command. The following are the details of the Chametz related commands and prohibitions:
Prohibition of eating Chametz:
It is Biblically forbidden to eat Chametz beginning from midday of Erev Pesach. This prohibition is listed as three negative commands; 1) Not to eat Chametz on Erev Pesach after midday; 2) Not to eat Chametz during the seven days of Pesach; 3) Not to eat Chametz mixtures [i.e. Taaruvos Chametz] during the seven days of Pesach. One who eats Chametz on Erev Pesach, past midday, receives Biblical Malkus. However, the Kareis penalty for eating Chametz only begins at night. This law is elaborated on in Halacha 3 and within the section of Kosher for Pesach foods and products, in chapter 6.
Prohibition against benefiting from Chametz:
It is Biblically forbidden to benefit from Chametz beginning from midday of Erev Pesach. This prohibition is included in the eating prohibition and does not contain an independent command. This law is elaborated on Halacha 4 and within the section of Kosher for Pesach foods and products, in chapter 6.
Tashbisu-The positive command to destroy Chametz:
There is a positive command for one to destroy his Chametz starting from midday of Erev Pesach. One who owns Chametz past this time transgresses this positive command, although is not liable for lashes. This law is elaborated on in Halacha 3 and within the section of Biur Chametz in Chapter 4 Halacha 17.
שִבְעַת יָמִים מַצּוֹת תֹּאכֵלוּ אַךְ בַּיּוֹם הָרִאשׁוֹן תַּשְׁבִּיתוּ שְּׂאֹר מִבָּתֵּיכֶם כִּי כָּל אֹכֵל חָמֵץ וְנִכְרְתָה הַנֶּפֶשׁ הַהִוא מִיִּשְׂרָאֵל מִיּוֹם הָרִאשֹׁן עַד יוֹם הַשְּׁבִעִי.
Baal Yiraeh and Baal Yimatzei-The negative command against owning Chametz:
There are two negative commands against owning Chametz throughout the seven days of Pesach, starting from the night of the 15th. One who owns Chametz past this time transgresses both of these negative commands, although he is not liable for lashes unless he purchases, or creates, the Chametz past this time. This law is elaborated on in Halacha 3 and within the section of cleaning for Chametz in chapter 3.
שִׁבְעַת יָמִים שְׂאֹר לֹא יִמָּצֵא בְּבָתֵּיכֶם כִּי כָּל אֹכֵל מַחְמֶצֶת וְנִכְרְתָה הַנֶּפֶשׁ הַהִוא מֵעֲדַת יִשְׂרָאֵל בַּגֵּר וּבְאֶזְרַח הָאָרֶץ.
מַצּוֹת יֵאָכֵל אֵת שִׁבְעַת הַיָּמִים וְלֹא יֵרָאֶה לְךָ חָמֵץ וְלֹא יֵרָאֶה לְךָ שְׂאֹר בְּכָל גְּבֻלֶךָ
There is a Rabbinical obligation which requires one to search for Chametz in all his properties and then destroy it. Biblically, it suffices for one to merely disown the Chametz prior to midday of Erev Pesach. This law is elaborated on in Halacha 7 and in the section of cleaning one’s house for Pesach in chapter 3 and the section of Bedikas Chametz in chapter 4.
 Admur Hakdama to Hilchos Pesach; Rambam in his Pesicha to Hilchos Pesach
 Admur ibid; Rambam ibid
 Rambam 1:8; Magid Mishneh ibid in name of Geonim; Rosh Tur
 Rambam 1:1
 Admur ibid
 Admur ibid
 Rambam 1:3