“On the eve of the fourteenth, we search for chametz by candlelight” (Pesachim 2a). I fondly recall hiding pieces of chametz all over the house and then helping my father, z”l, find them as we began the formal preparations for Pesach. While not as “rewarding” as hiding the Afikomen, bedikat chametz, the search for chametz, is much more important.
The reason we do so is a matter of debate. Rashi understands that the purpose of bedikat chametz is to ensure one does not violate the Biblical prohibition of ba’al yera’eh and ba’al yematzei, the prohibition of owning chametz, and of seeing the chametz that one might unlawfully own during Pesach.
The Talmud (Pesachim 4b) notes that on a Biblical level, bitul chametz—the nullification of any chametz that one may own, declaring it to be no more than the dust of the earth—is sufficient to absolve oneself of violating the prohibition of ba’al yera’eh and ba’al yematzei. By making the chametz hefker, ownerless, one can no longer violate the prohibition of owning chametz.
Nonetheless, the Talmudic rabbis required one to search for chametz the night prior to Pesach and follow that up with biur chametz, by burning it, on the morning of erev Pesach. Declarations are all too often ignored and, at times, not even made in a serious vein in the first place. And if the declaration of bitul chametz is not intended seriously, then one would be in violation of ba’al yera’eh and ba’al yematzei. Not wanting to rely on a possibly meaningless bitul alone, the requirement of bedikat chametz was added. Actions speak louder than words: bitul must be followed by bedikah and then biur.
The Tosafists, on the other hand, disagree. If one’s concern was ba’al yera’eh and ba’al yematzei there would be no need, the Tosafists claim, for bedikat chametz; bitul would, in fact, suffice. Tosafot has a more serious concern: namely, that if we did not search for and rid our homes of chametz, one might actually come to eat it. Bitul requires that we declare our chametz as ownerless, but does not require that we rid our home of chametz. Yet being so used to eating chametz 358 (or 357) days a year, if we do not search for and remove all chametz from our home, it is almost inevitable that one will come to eat chametz on Pesach. Hence, the need for bedikat chametz. On the other hand, there is little fear that one may accidentally eat non-kosher food and hence one may, if need be, keep non-kosher food in one’s possession.
Bedikah is all the more necessary when we consider that eating chametz carries the punishment of karet, excision, a much more serious Torah violation than ba’al yera’eh and ba’al yematzei which, as a negative command violated passively, is the “least” severe of negative Torah transgressions.
Bedikat chametz is a protective fence ordained by our Sages, lest we violate either the biblical prohibition of ba’al yera’eh and ba’al yematzei, or of eating chametz—or both. It is a fulfilment of the duty to “put a fence around the Torah”, lest we accidentally violate Torah law.
Yet in a fascinating insight, Rav Zevin—in his masterful sefer, Moadim BeHalacha—notes that the biblical prohibition of ba’al yera’eh and ba’al yematzei is itself a protective fence, lest we violate the even more serious prohibition of eating chametz. According to Rashi, we do bedikah to prevent violation of ba’al yera’eh and ba’al yematzei, and ba’al yera’eh and ba’al yematzei helps to prevent us from inadvertently eating chametz. Tosafot would argue that ba’al yera’eh and ba’al yematzei is the Torah’s way of protecting us from eating chametz. To that, the Rabbis added an additional protective fence of bedikat chametz, giving us a very strong fence indeed.
While we tend to think of protective fences as a rabbinic institution, as a rabbinic means to ensure we not violate the Torah. That the Torah itself has mitzvot which themselves are a means to an end sounds somewhat strange. Yet that such exist in the Torah itself is quite clearly enunciated. “Seven days you shall eat unleavened bread; on the very first day you shall remove leaven from your houses, for whoever eats leavened bread from the first day to the seventh day, that person shall be cut off from Israel” (Shemot 12:15). The Torah quite clearly tells us we must remove chametz from our homes—failure to do so violates ba’al yera’eh and ba’al yematzei—lest we come to eat chametz.
This should not surprise us. The Torah itself is, in many ways, a means to an end, guiding us to become "a kingdom of priests and a holy nation" (Shemot 19:6). As the Ramban notes, one can technically observe all the mitzvot of the Torah, and yet be a "naval bershut haTorah, a disgusting person with the permission of the Torah". It is not enough to observe the letter of the laws of the Torah. One must observe the spirit of the laws too. Hence the Ramban explains the need for the meta-obligations to be holy (Vayikra 19:2) and to do "the straight and the good" (Devarim 6:18).
Masechet Pesachim begins with the relatively minor law of bedikat chametz. But as Malcolm Gladwell demonstrated in The Tipping Point (Little, Brown and Company, 2000), the little things can make all the difference.
 Of course, this is exactly what happens with mechirat chametz, our sale of chametz. This is something that was almost unknown to our Talmudic rabbis, and surely not the way it is done today. That being said, modern methods of refrigeration and storage would make getting rid of our chametz economically ruinous, not to mention extremely wasteful. As the “Torah has mercy on the money of Israel” (Rosh Hashannah 27a), our rabbis allowed and encouraged us to sell our chametz, even as the food stays locked away in our home. Please G-d, we will elaborate on this in a future post.
 Other laws in the Torah that are there to protect other, more important laws might include the prohibition of a king to have many wives, lest he be led astray; and the prohibition to “come close” to a niddah, lest one engage in sexual relations. Such a phenomenon likely exists even amongst positive mitzvot. Hence, the command to write a sefer Torah—so that we can learn and teach Torah.