One might wonder why we break off a piece of matzah now at the very beginning of the Seder rather than later at the time of the blessing when we actually eat it. The simple answer is that we need the broken piece throughout the Seder while we describe the redemption as a visible symbol of the  lehem oni, bread of affliction, our fathers ate in Egypt. On a deeper level, the very act of breaking a piece of "bread" in two and saving for later demonstrates its character as  lehem oni.  Only a poor person who does not know when or if his next meal will come breaks off from what he has now and saves it for later. 

Interestingly, matzah is also the symbol of redemption. It is the food that our ancestors ate while leaving Egypt in haste. The dough had no time to rise, because the time of redemption had come and there could be no dely. The Seder is thus filled with paradox. It makes you feel the servitude as well as the redemption, the sorrow as well as the exultation.


haggadah Section: Yachatz
Source: The Passover Haggadah by Rabbi Shlomo Riskin