I was wondering why—and I assume this came before the Catholic/Greek split—the church changed the Sabbath from Saturday to Sunday.
I never realized it until a Jewish friend mentioned that their Sabbath was Saturday. When I thought about it, I realized that Saturday was the the Seventh Day on which God rested after creating the world.
Also, the word for Saturday in many European languages is a variation of the word Sabbath (e.g., in Italian, Sabato).
The Saturday Sabbath is appropriate to the Old Testament.
In the New Testament—which celebrates the resurrection of Christ on the first day of the week—the central experience of our faith as Christians is commemorated every Sunday of the year. We find the fulfillment tothat which was revealed in the Old Testament.
We are under no more obligation to follow the Saturday Sabbath than we are to follow Old Testament dietary restrictions—upon which today’s Kosher laws are derived—or to practice circumcision as a sign of our covenant with God.