The story of Pesach starts the day before the festival. Pesach is the only festival with preconditions that are critical in order to keep its laws. The evening before the seder, after the stars come out we check our houses for chametz:
"On the eve (in hebrew – Or – light) of the fourteenth we check for chametz by candlelight",
the next morning we burn the chametz and completely cancel it by saying :
"Any Chametz I have in my property, that I haven’t seen or destroyed, is nullified as if it is dust".
The main part of the removal of chametz is not the checking of our houses or the burning – these are all rabbinical additions, the main part is nullifying the chametz in our hearts! Our Rabbis define the mitzvah as follows:
"One must nullify the chametz in one's heart, think of it as dust, and positively think that one doesn’t own any chametz at all"
As we shall see, this mitzvah is the gateway to the story of the exodus , both then and now.