http://revach.net/article.php?id=4454

Section: Parshas HaShavua   Category: Quick Vort
Parshas Vayikra: Netziv - Chometz On Pesach, Chometz On The Mizbei'ach
"Lo Sei'aseh Chametz Ki Chol Si'or... Lo Saktiru Mimenu Isheh Lashem" (Vayikra 2:11).  The two places that the Torah forbids Chometz is on the Mizbei'ach all year round, and in every person's home on Pesach.  Why is this?

The Netziv in Hemek Davar says that leavening bread is using human intervention to add on to the natural state of the creation.  The closer we are to Hashem the less appropriate it is for us to alter the natural order and manipulate the Briah.  Therefore in the Bais HaMikdash, the dwelling place for the Shechina on earth, it is inappropriate to ever have Chametz on the Mizbei'ach to be offered up to Hashem.

Similarly, Pesach is the Yom Tov that imbues Emunah into our souls.  Yetzias Mitzrayim is the banner we wave as the proof of Hashem's control over the world and His love for us, and we frequently mention Zeicher Litzias Mitzrayim.  During this Yom Tov where we bask in the arms of our great Protector and Father in Shamayim, we refrain from eating any Chametz and leave the Briah as He made it, without our intervention.