תּפֿילה אויף שמות 1:14

This marror [bitter greens] that we are eating, for the sake of what [is it]? For the sake [to commemorate] that the Egyptians embittered the lives of our ancestors in Egypt, as it is stated (Exodus 1:14); "And they made their lives bitter with hard service, in mortar and in brick, and in all manner of service in the field; in all their service, wherein they made them serve with rigor."