A thorough search for chametz is carried out by night – the Mishnah says, “by the light of a lamp”.
By this stage our spring cleaning has been done, but there is always a chance of finding chametz in a nook or cranny. The search is valid even if nothing is found, but to help it along there is a custom of taking ten hard pieces of chametz and placing them around the house where they can be discovered, though the search is valid without them.
The custom is referred to in Isserles’ glosses to the Shulchan Aruch, Orach Chayyim 432:2 and is said to allude to the ten sons of Haman, who were their father’s henchmen and had to be removed. The link between Purim and Pesach symbolises the chain that binds the whole Jewish year. The ten pieces ensure that there will be some chametz to destroy.
The search is done by the light of a lamp because of the verse, “The spirit of man is the lamp of the Lord, searching all the inward parts” (Prov. 20:27).
Just as the soul lights up the body and identifies the failings in a person’s life, so the Lamp of the Lord peruses every corner of the Creation, with nothing escaping its scrutiny; likewise, every home must check to see if anything untoward is present.