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An interfaith group in town is holding a Jewish-Christian seder. My church has held a Christian seder for several years, but I've never heard of a seder being jointly held by the two faiths. Any idea how common this is and what I should expect if I go?

A joint Jewish-Christian seder can give members of both faiths a chance to understand each other's traditions and beliefs--literally on the spot and possibly through each other's eyes. Jews can see how--and maybe why --Christians equate their Savior with the blood of the lambs that saved the ancient Israelites on the eve of the Exodus; Christians can see how--and maybe why--Jews observe the full seder, one whose basic forms have been passed down from generation to generation starting near the end of the first century, C.E.--forms which are still evolving and still adapting to new and contemporary interpretations of the Passover story.

But let's set the record straight: The Last Supper, an event that according to the New Testament occurred circa 30 C.E., did not resemble the seder as Jews know it today: a meal with several important elements that are eaten in a certain way for certain symbolic reasons. The seder as we know it today didn't even begin to develop until after the Temple in Jerusalem was destroyed in 70 C.E., about 40 years after Jesus was crucified.

In fact, even in the gospels, there are timing discrepancies regarding Jesus and Passover. Mark, for instance, says Jesus and the apostles had a Passover meal the night before his crucifixion; at the meal, Jesus interpreted the bread and wine served as his body and blood. But in his gospel, John mentions only a supper at which Jesus washes his disciples' feet. He also places the crucifixion before Passover.

Over the centuries, Christians embraced the idea of Jesus as the paschal sacrifice, and also the idea that John the Baptist, who baptized Jesus, was a symbolic successor of the prophet Elijah. Traditionally, the return of Elijah was supposed to herald the arrival of the messiah. That dovetailed nicely with Jesus as the messiah, as well as with the cup of wine that emerging tradition required be placed at the seder table for Elijah.

If there was a Last Supper--and historians and theologians disagree about that--then it almost surely did not have anything to do with the seder as we know it today, other than the fact that a lamb was sacrificed and then consumed. And it's highly doubtful that Jesus and the disciples ate matzah at that supper. It's that misconception which has persuaded many Christians to have their own versions of seders, one at which the death of Jesus is equated with the slaughter of the paschal lamb. The enslaved Israelites had used the blood from the lamb to mark their doors the night the Angel of Death came to slay the first-born sons of the Egyptians. When the angel saw the blood, he passed over the homes of the slaves.

Before the destruction of the temple in 70 C.E., celebrating Passover centered around sacrificing lambs at the Temple. People throughout ancient Israel would throng to Jerusalem; according to the usually reliable historian Josephus, as many as three million people filled Jerusalem in 65 C.E.

Since the Temple was the only place where sacrifices could be offered, upon its destruction Passover observance became more ritualistic and symbolic and was influenced by such Hellenistic and Roman qualities as gathering for discussion and banqueting. Especially common to the Roman elite was reclining at the dinner table, dipping the food into saltwater, and serving certain hors d'ouvres--all of which were incorporated into the seder and none of which Jesus and the disciples would have experienced at the Last Supper.