The prohibition against ḥametz on Pesaḥ is especially stringent, for the Torah not only forbade eating it, but commanded that it not be seen nor found in our possession. Our Sages further forbade eating any food with even the slightest amount of ḥametz mixed in. Thus the avoidance of ḥametz on Pesaḥ is absolute. This is because ḥametz symbolizes evil, as it says in the Zohar (2:40b) that ḥametz is the evil impulse. Specifically, it alludes to the impulse of pride. Fermentation causes dough to rise – it looks as though the dough is inflating itself and puffing up with pride, as an arrogant person would. In contrast, matza, which remains in its original size, as it was when God created it, symbolizes the trait of humility.
At first glance, this is difficult to understand. If ḥametz represents the evil inclination, why is there no commandment or custom to avoid it throughout the year? On the contrary, humanity is praised for knowing how to make wheat into fine ḥametz cakes (see Tanḥuma Tazri’a 5). This was the Creator’s purpose in endowing human beings with the wisdom and practical skills to engage in developing the world. God created an imperfect world intentionally, so that human beings could imitate God’s deeds and take part in improving the world by developing science and technology through diligent work. In other words, human beings are enjoined to improve and expand nature through a process that is perfectly analogous to turning wheat into baked goods. Thus, ḥametz is a good thing.
The answer is that there are two types of pride: One is that man exaggerates his own praiseworthiness and thinks he is wiser, stronger, and better than he really is. Any intelligent person understands that such pride harms one’s ability to actualize his potential, for it impairs his ability to judge, he cannot conduct his life properly, and instead of being happy with his accomplishments, his life is filled with errors and disappointment. Such pride is inappropriate all year long and has nothing to do with the prohibition of ḥametz. On the contrary, such pride distracts people from producing good things for the world.
The second type of pride, which the prohibition of ḥametz on Pesaḥ is designed to root out, is a person’s pride vis-à-vis his Creator, his God. Jewish faith is predicated on the acknowledgment that God created the world and determined its destiny, and that the roots of all things depend on Him alone. Although God gave humanity the ability to improve and to develop the world, this is limited to manipulating and developing the derivatives of the core elements of creation; human beings have no power over those core elements, which are divine creations. God created the world, gives life to all people, chose the people of Israel to be His am segula, His treasured nation, and gave Israel the Torah. Human beings have no authority to call these fundamental principles into question. Therefore, when one stands before his Creator, he must envelop himself in humility and make every effort not mix his human thoughts with the fundamental principles of creation. Such confusion, like ḥametz on Pesaḥ, is forbidden. Just as suicidal thoughts are fundamentally flawed because our lives are a gift from God and not ours for the taking, so too, one who mixes human ideas into the principles of faith inevitably emerges with flawed ideas.
Pesaḥ, and especially the Seder, is designed to instill in us the fundamentals of faith: that the world has a Creator, that He watches over His creatures, and that He chose the people of Israel to reveal His name in the world. Whenever an aspect of the divine is revealed in the world, it appears in a completely miraculous fashion, to show that it is not a human endeavor. Thus, the Exodus was accompanied by signs and wonders, to make public that the election of Israel was a divine matter. Similarly, the Torah was given with obvious miracles, to a generation that lived miraculously for forty years in the desert, in order to make it known that this was an entirely divine matter. In other words, we receive the fundamental principles of faith from God – we do not invent them. Whoever mixes some human aspect into these basic principles of faith is guilty of idolatry. This is alluded to in Zohar’s statement that ḥametz on Pesaḥ is idolatry (2:182a).
Therefore, on Pesaḥ, the holiday geared toward imparting the fundamentals of faith, we are commanded to be extremely cautious to avoid eating and possessing even a smidgen of ḥametz, which symbolizes our human aspects that must not get mixed in when we speak about the roots and foundations of faith. During the rest of the year, however, when we nurture and improve the branches that develop from these roots, ḥametz is allowed and even desirable.