That is a pretty funny statement there from a Catholic. How about the Commandment to keep the Sabbath day holy? The Sabbath day, you remember that don't you? The seventh day of the week. Luke 4:16 tells us Jesus had a custom of worshiping on the Sabbath Day. Are we to do the same? Exodus 20:8 starts off with Remember the Sabbath as if people would forget it. Hidden poison indeed.
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. 1:3); the day when Christ rose from the dead; the day when the Holy Spirit came upon the Apostles (Day of Pentecost). The 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. Instead “The Sabbath, which represented the completion of the first creation, has been replaced by Sunday, which recalls the new creation inaugurated by the Resurrection of Christ” (CCC 2190). Sunday is the day Catholics are bound to keep, not Saturday.
(http://www.catholic.com/quickquestions/did-the-early-church-move-the-sabbath-from-saturday-to-sunday)