Chametz and Matzah and the Yetzer Harah

Interesting that Chametz is so Chamur as we see that there is an Issur of Ba'al Yera'eh Uba'al Yimutzeh and a mitzvah of Tashbisu and we know that Chazal were so machmir that they said that Chometz is Assur Be'mahshehu and cannot be diluted even one to sixty. There is no issur in the Torah that is nearly as stringent as Chometz. On the other hand the Torah obligates us to eat Matzah. Imagine of there was no Mitzvah of Matzah in the Torah. Eating Matzah would probably be considered a terrible sin. The Torah is full of siyugim and gedarim "Asu Siyag Latorah" The concept of Shevus may be Deoraisah. So how/why does the Torah be so machmir on chametz on one hand and obligate us to eat Matzah on the other hand?

If we look at the pnemiyus of the inyan we know that Chamietz represents the yetzer horah. As the Gemarah in Berachos says that the reason that people do aveiros is because of the Se'or Shebi'isah which Rashi translates as the Yetzer harah. The seforim explain that this is the reason for all the chumros of Chametz. The lesson is that man must completely eradicate the yetzer harah from himself totally to the point where it is "Mushbas" and the Yetzer harah should be "Ba'al Yera'eh Uba'al Yimutzeh". Taking this concept further, Matzah represents getting as close to the Yetzer harah as possible without any shemetz of the yetzer harah.

The obligation to eat Matzah in other words is an obligation to live a life that brings us very very close to the "Se'or Shebi'isah without crossing the line. Life must be lived to its fullest extent as long as there is no crossing the line. That is the Shevil Hazahav that the Rambam mentions. If one drifts to far away from Matzah too he is off the derech also.