There's a name for it? I've been wondering why some of my protestant friends have been getting more wrapped up in understanding Jewish practices.
I wrote a lengthy facebook note about this trying to connect the dots between the Old and New Testaments, and the Early Church according to the Church Fathers and the Roman Catholic Church.
Basically my friends are working from the assumption that Christianity got corrupted somewhere along the line and that the best thing for Christians to do is imitate the Early Church, and that the Early Church was something like the Book of Acts and not far removed from Jewish practice. Well, they are right on some things and wrong on others.
My task was basically to show that Catholicism preserves the continuity between Old and New Testaments better than protestant Christianity because of the Mass and Eucharist. I had to show that the sacraments are the fulfillment of OT prophecy and Jesus' teachings, and I had to remove misconceptions that they had about the "potluck and praise service" nature of the early church by using quotes from the Church Fathers to show that the early Christians also celebrated the Eucharist and had liturgy etc, and by showing that the Last Supper (Passover Seder) was a solemn liturgical feast.
I quoted a lot from the "for Protestants" section of the Fisheaters website about the nature of the priesthood etc. And I also used ideas from Scott Hahn's "The Lamb's Supper". I know some people on this forum aren't fans of Hahn, but he does speak "protestant" pretty fluently
Unfortunately no one has responded to me yet so I can't tell you how it worked ;)