As the Jews leave Egypt they take dough with them, which they bake into unleavened cakes, known as matzah (pl. matzot). On the simplest level, the only difference between a loaf of bread and matzah is that the bread is inflated and matzah is flat. Matzah is the food of a humble slave, who does not have time to let the bread rise, and who eats foods that will leave him feeling full for hours afterwards. For this reason, matzah is also called lechem oni, the bread of affliction or poverty. Matzah commemorates the bread of slavery that the Jewish people ate in Egypt, prepared in haste, without the luxury of time to let it rise.
The fact that the Jewish people also ate matzah, slave food, at the moment of their redemption indicates that the Jews were powerless to save themselves. They were slaves up to the last moment, and only through G-d’s miraculous intervention did they go free. Rabbi Samson Raphael Hirsch explains that Jews ate matzah on the eve of the Exodus
“…so that in the great hour of liberation it would be impressed deeply on their minds that they had contributed nothing to their liberation, that in the very hour of liberation they were still slaves eating the bread of affliction until the word of G-d created anew the freedom which had been wrested from man…”
Thus did unleavened bread become an everlasting memorial throughout the generations to the redemption from Egypt brought about by G-d alone.
The matzah, therefore, teaches us that the Jews did not leave Egypt through a successful slave revolt. It symbolizes that the Jews were not liberated through outstanding human leadership, bravery or military cunning. Understanding the Exodus inspires us with humility and gratitude to G-d.”
Eating matzah also reminds us of another reason for gratitude. The Jews were in Egypt for 210 years and suffered slavery under a brutal and oppressive regime. In addition to physical servitude, the Jewish people suffered spiritually: they abandoned the pure monotheism of Abraham and began to worship Egyptian G-ds. Many Jews lost hope of ever leaving Egypt or becoming free: over time, they began to consider themselves Egyptians. According to some sources, as many as four-fifths of the Jewish people died in Egypt before the Exodus. Some suggest that they may not actually have died, but rather ceased to exist as Jews and remained as Egyptians in Egypt.
Kabbalists describe the spiritual state of the Jewish people in Egypt as having descended to the 49th level of impurity. Had they stayed in Egypt even one moment longer and reached the 50th, last level, they would have assimilated entirely into Egyptian culture and been lost forever. G-d took the Jews out with haste because they were at the brink of oblivion. The departure was so hasty that the Jews did not even prepare food for the trip, and did not even have time to bake regular bread – they ate matzah because they got out “just in time.” So another reason we eat matzah is in recognition of G-d’s kindness in getting us out at the right moment