Seder.

Our pastor's homily for the Mass of the Lord's Supper (Holy Thursday — my favorite Mass of the year) told me something I didn't know.  "There are traditionally four cups of wine drunk at the Passover meal," he said, "and the one you drink when you break the bread, the one described in John's Gospel when Jesus institutes the Eucharist, is the third of the four cups."  He went on to point out that Jesus makes a point of telling his disciples he isn't going to have the fourth cup that evening.  So they leave the upper room with the Passover meal incomplete.  This Passover celebration must include the Cross.

I realized I actually didn't know that much about the Passover Seder.  I found theWikipedia entry enlightening, and I suppose there must be even better resources out there.  But if you know nothing about how the Passover meal is traditionally celebrated, it will surely help place in context the descriptions that appear in the various places in the New Testament.  Such as the breaking of the bread:

At the head of the table is a Seder Plate containing various symbolic foods that will be eaten or pointed out during the course of the Seder. Placed nearby is a plate with three matzot [unleavened breads]….The three matzot…are connected to the three Patriarchs, Abraham, Isaac, and Jacob…

The middle of the matzot on the Seder Plate is broken in two. The larger piece is hidden, to be used later as the afikoman, the "dessert" after the meal. The smaller piece is returned to its place between the other two matzos.

Huh, the second of three breads is broken and part of it returns to the other two while the other part is hidden.  It's not hard to imagine how deeply the story resonated with those early Christians who had taken the message of Passover in with their mother's milk.