Most people assume that the Matzah that we eat at Seder night commemorates the Matzot that Klal Yisrael baked when they left Egypt. They left so quickly that there wasn't time for the dough to rise. However, they didn't leave Egypt until the morning following the "slaying of the firstborn." If our eating of the Matzah represents the Matzah that they baked when they left Egypt, then the Mitzvah of eating Matzah should also be observed in the morning. Rather, the Matzot that we eat at the Seder alludes to the secret of the Matzot of the daily Minchah offering that the Kohanmim ate in the Temple. The Torah tells us that Matzot of the Minchah offering were made without any leaven, because leaven in dough symbolizes the negative impulse in the heart of man. The Kohanim ate the unleavened Matzot of the Minchah offering with the highest level of holiness - "Kodesh HaKodishim."
On the night of the"slaying of the first-born," HaShem revealed the Shechinah to Klal Yisrael. The Shechinah sanctified all of Klal Yisrael with great holiness and separated them from the defiled Egyptians, who were immersed in idol worship. This night was also called, "Lil Shimorim" - a night of guarding" because HaShem protected Klal Yisrael from all negative and impure forces. In commemoration of the great holiness that Klal Yisrael attained in Egypt, we eat Matzot, which are imbued with great holiness. Each Pesach eve, the same great holiness that HaShem revealed to Klal Yisrael in Egypt, is again revealed to us when we fulfil the Mitzvot of the Seder, especially the eating of holy Matzah.
Application: When you fulfil the Mitzvah of eating Matzah at the Seder, imagine that you are a Kohen eating the daily Minchah offering in the Beit HaMikdash. Sense the wonderful holiness, purity, and spiritual elevation that HaShem grants to us at this special occasion. Reflect on HaShem protecting you from all negative and impure forces. Feel the joy of coming close to the light and holiness of the Shechinah, Kodesh HaKadoshim.
(Based on the commentary of the M'Harashah to Pesachim 116)
