שבעת ימים שאור לא ימצא בבתיכם
שמות יב – יט
What
Chametz [leaven] should not be found (Loosely: Do not have Chametz)in ones premises for all seven days of Pesach.
Type
Negative
When
Any time
Where
Any where
Who
Males and females.
Why
So we remember the miracles we saw in Egypt, and especially that Hashem took us out so quick that we needed to bake our dough as Matza.
Additional details
In the 1st, 2nd & 3rd perek of Psachim
If one does it
He has transgressed 2 negative commandments, בל יראה ובל ימצא. However he does not get lashes unless he transgresses with an act, such as bringing Chametz into his premises, or making a dough chametz. This, because we Pasken Le`Halacha that transgressing without an act does not get lashes.