Humility Vs. Pride
The Torah portion , Bo, contains the commandment to observe Passover: "For seven days you shall eat matzot." The Biblical obligation to eat matza on Passover applies in our times as well.
How are chametz (leavened bread) and matza different? Both contain flour and water, so what makes matza unique? What can we learn from the mitzva to eat matza on Passover and the prohibition against eating chametz?
Chametz is dough that was allowed to rise and grow in bulk. Matza is dough that is thin and flat; even after it is baked it remains the same height as before.
Chametz is symbolic of pride and elevation, of arrogance and an inflated sense of self. It is symbolic of a person who considers himself superior to everyone else around him.
Matza, by contrast, is symbolic of humility and self-abnegation. Its flat dough symbolizes a person who is completely nullified to others - the exact opposite of chametz.
The Hebrew letters of the words chametz and matza are almost identical: chet-mem-tzadik, and mem-tzadik-hei. The only difference between them is one letter (i.e., one word contains a chet, the other a hei). Furthermore, the chet and the hei are almost the same shape; both are formed with three lines and have an opening at the bottom.
This opening at the bottom alludes to the verse in the Torah "sin lies at the opening" - the space through which sin can intrude upon an individual and cause him to transgress.
Here we see the important distinction between chametz and matza: The chet in chametz is completely closed at the top. The sin that has entered cannot escape; it remains inside and can't get out. The person who has committed a sin finds it difficult to let go, to abandon his wrongdoing and distance himself from transgression.
The hei in matza, however, has a small opening at the top - the opening through which a person can repent and return to G-d. Yes, it's only a small opening, but all that is necessary is one small move in the right direction, and G-d accepts our repentance and helps us return.
Chametz is symbolic of a person swollen by his own self-importance. If he sins it is very difficult for him to admit having made a mistake. He will always find excuses to justify his actions. A person like this is trapped within the "chet" and cannot find his way out.
Matza, on the other hand, alludes to a person who is modest and humble. If he sins, he doesn't try to justify what he's done, but is immediately sorry and regretful. His heart is broken, and he is aroused to repentance. Through the tiny opening in the hei he draws nearer to G-d; he corrects his behavior and returns to Him with a full heart.
Adapted from Likutei Sichot, Volume 1