This is a common misunderstanding. Catholics do not worship on the Sabbath, which according to Jewish law is the last day of the week (Saturday), when God rested from all the work he had done in creation (Gen.2:2-3). Catholics worship on the Lord’s Day, the first day of the week (Sunday, the eighth day); the day when God said Let there be light (Gen.he Catechism of the Catholic Church says: The Church celebrates the day of Christ’s Resurrection on the ‘eighth day,’ Sunday, which is rightly called the Lord’s Day (CCC 2191). The early Church did not move the Sabbath from Saturday to Sunday.