Rabbi Gamaliel (The teacher of Paul) used to say: Whoever does not explain these three things on passover does not discharge his duty, and these are they:
  • the passover-offering.
  • Unleavened bread, and
  • bitter herbs.
The passover-offering is [sacrificed] because the omnipresent passed over the houses of our fathers in egypt, as it is said, then ye shall say: it is the sacrifice of the lord's passover, for that he passed over etc. (Shemot/Exodus 12:27).
The unleavened bread is [eaten] because our fathers were redeemed from Egypt, as it is said, and they baked unleavened cakes of the dough which they brought forth out of egypt etc. (Shemot/Exosua 12:39).
The bitter herb is [eaten] because the egyptians embittered the lives of our fathers in Egypt, as it is said, and they made their lives bitter etc. (Shemot/Exodus 1:14).
(Babylonian Talmud Pesachim 116a,b)

haggadah Section: Introduction