The word seder is a Hebrew term. It means "order." The Passover Seder is the order of celebrating the traditional Passover meal.
Passover looks back to the deliverance of Israel from bondage in Egypt about 1500 years before Christ. The Lord sent ten plagues against Egypt to bring them to the place where they would allow God's people to leave. The last plague involved the death of every first born child in Egypt that did not take refuge in a home with the blood of a sacrificial lamb over the door. God promised to "passover" the homes so marked so that all would be safe inside.
While safely inside homes covered by the blood of a lamb, the Israelites ate a meal of the roasted lamb and other ingredients. After their rescue from Egypt, the Lord commanded Israel to celebrate that meal on an annual basis to remember the miraculous deliverance God accomplished for His people. The spirit of the celebration is something of a mix betweeen the bounteous dinner of Thanksgiving and the celebration of independence on the Fourth of July.
When Jesus ate His last meal with His disciples, it was a Passover meal. The New Testament even calls Jesus our Passover lamb (1 Corinthians 5:7). It was during that celebration of Israel's salvation from bondage that our Lord took two of the elements from that orderly meal (the bread and the cup) and established a new memorial celebration - the Lord's Supper.
At Terrell Bible Church we have an annual Passover Seder. We celebrate the meal on the Thursday before Easter - the night our Lord met with His disciples before His death and resurrection. Our goal is to demonstrate the significance of our Lord using the Passover meal as a foundation for our continuing remembrance in the Lord's Supper. We have a roast lamb dinner and follow the order of the meal that our Lord would have celebrated with His disciples. We hear some of the Hebrew prayers that would have been used that evening by our Lord. Our desire is to renew the sense of wonder and worship that comes as we think of our Lord's sacrifice on the cross for us.