Okay, bear with me.
I grew up celebrating Passover every year. At the passover seder, we all broke and ate the matzoh and drank the four cups of wine. Everyone at the table. When I was twelve, my immediate family went to a messianic seder hosted by my second cousin, who is a messianic jewish rabbi. We were unofficially banned from my extended family's jewish seders from then on. Everyone in my family, youngest to oldest, was banned – even though my father was the one who made the decision to attend the messianic seder. (I guess my relatives understood the concept of covenant headship.) So we went to a different table, a messianic table. We all went and ate and drank at that passover table, now commemorating the death of Christ.
This past Thursday was my first Maundy Thursday church service. Growing up (since I was twelve) we commemorated Maundy Thursday with an actual seder. Of course, we didn't call it Maundy Thursday. We called it Passover.
So at our church's Maundy Thursday, as opposed to every other Sunday ("Why is this night different from all others?"), it seemed we were really (and appropriately) hammering on the connection to passover and the seder. And it kept bringing me back to the seders I'd attended growing up. And I remembered feeding wine and bread to my cousin when he was no older than one, and could only just chew and swallow. This was the level of participation he offered at the seder despite that he had no concept of what was going on, he could not read and he could not speak the confessions or prayers recited during the meal. And yet we wouldn't have even thought of withholding the bread and wine from him (and the karpas, and the maror, and the korech). In fact, wherever the baby's faculties keep him from participating, we act for him. (For example, during the urchatz – the washing – we wash their hands for them.) Even more, the youngest child who can speak is given a special role at the seder; nevertheless, speaking and the ability to ask the Four Questions is not a requisite for admission to the table.
Again, on Maundy Thursday we as a congregation affirmed that what we celebrate is actually the last supper, the passover seder, freely offered to all members of the covenant community. And then I was made to withhold the bread and wine from my son, who was baptized into the covenant, just as my cousins and I were circumcized into the old and failed covenant. So what is it? Are we celebrating the seder or not? If so, how could it be so different than the seder I celebrated growing up? How could we do something in the Church of Christ that would be unthinkable to my un-believing relatives, who always celebrated with great relish the day that the youngest child at the table first took their matzoh and wine, i.e., the day a weaned baby celebrated his first seder.
So what am I to think? Are we celebrating the last supper, or are we celebrating the communion as distinct from the last supper? Did my Jewish relatives, who follow the same seder liturgy (though the true meaning is obscured by unbelief) every year in the same basic way as Christ did, have it all wrong? Or is there biblical reason to alter the fundamentals of the seder?