Sefer Ha’mitzvos Ha’Katzar (the concise book of mitzvos)
By the Chofetz Chaim
This book lists the Torah mitzvos that can be observed today
First Section – the Positive Commandments
22. It is a positive commandment to destroy chametz on the fourteenth of Nissan
As it says in Shemos (Exodus) 12:15, “Only on the first day, destroy leaven from your houses.” From the Oral Law we learn that the first day means the fourteenth of Nissan before the time that it is forbidden to eat chametz. The destroying is burning all known chametz in one’s possession and, for the chametz that is not known, a person should make it void in his heart and consider it as nothing – that he has no use for it at all.
From the teaching of the Sages, the search for and examining should begin on the night of the fourteenth by the light of a candle, because all people are found in their houses during the night and the light of the candle is good for searching.
This is obligated in all places and at all times, for men and for women.