The Seder, celebrated on “Maundy Thursday” (a.k.a, “Holy Thursday”), tells the story of the Passover event and meal from the book of the Exodus in the Old Testament. This is important because this is the event Jesus was celebrating with His disciples for His last supper (and instituted the Sacrament of Holy Communion); and He didn’t choose this connection arbitrarily.
Jews the world over celebrate the Seder as a reminder to the Passover. For Christians, we see the deep and deliberate connection of the Passover and Jesus as “the Lamb of God who takes away the sins of the world” (John 1:29). We will see the how God has saved us from death by the blood of His Lamb, Jesus, just as He saved Israel from death through the blood of lambs in the Exodus.
And all of this will tie into the Passion of Jesus through Holy Week as well as Holy Communion.
See also lifebridgesealy.com/tag/seder.