Negative commandment · Lo Ta’aseh #197 of 613
Not to partake of chametz on Pesach
שלא לאכול חמץ בפסח
The verse · Shemot 13:3
וַיֹּאמֶר מֹשֶׁה אֶל־הָעָם זָכוֹר אֶת־הַיּוֹם הַזֶּה אֲשֶׁר יְצָאתֶם מִמִּצְרַיִם מִבֵּית עֲבָדִים כִּי בְּחֹזֶק יָד הוֹצִיא ה׳ אֶתְכֶם מִזֶּה וְלֹא יֵאָכֵל חָמֵץ
“And Moshe said to the people, Remember this day, in which you came out from Miżrayim, out of the house of bondage; for by strength of hand the Lord brought you out from this place: no leavened bread shall be eaten.”
The Rambam’s words
Not to partake of chametz on Pesach, as [Exodus 13:3] states: "Do not eat chametz."
שלא לאכול חמץ בפסח, שנאמר "לא ייאכל, חמץ" (שמות יג,ג).
Who & when
“And [it] is practiced in every place and at all times by males and females.”
Where in the Mishneh Torah
Hilchot Leavened and Unleavened Bread הלכות חמץ ומצה