The Jewish Sabbath celebrates the completion of creation. It became a day of rest and today is strictly observed by Orthodox Jews as well as by multitudes of Christians. Sunday was chosen because it was understood that Jesus was resurrected on Sunday. The manipulation of the Sabbath has been notable throughout the centuries especially during Inquisitions when Jews were persecuted for practicing Sabbath on Saturday.
Suellen Ocean is the author of Secret Genealogy a how-to for tracing ancient Jewish ancestry and Secret Genealogy II, Uncovering the Jewish Roots of Our Christian Ancestors, both available at Amazon, B&N and Ocean-Hose.