At the Passover Seder, why do Jews recline while drinking the four cups of wine or eating Matzah?
The whole celebration of Passover is to remember the freedom the Jewish people fought for. The Exodus from Egypt or the fleeing from slavery was an important part of Jewish history.
Anytime wine is drank or Matzah is eaten during the Seder, reclining symbolizes the luxury of freedom. In ancient times, the only people who could recline while eating or drinking were people who were free.