Seventh-day Adventists have always quoted Roman Catholics in showing that the Catholic Church admits that she changed the Sabbath to Sunday. One of the best known is in Great Controversy, page 448:
Romanists declare that "the observance of Sunday by the Protestants is an homage they pay, in spite of themselves, to the authority of the [Catholic] Church." - Mgr. Segur, Plain Talk About the Protestantism of Today, p. 213.
On January 5, 2006, Roman Catholic scholar and apologist, Patrick Madrid, made a startling statement of which every person who loves the true Sabbath should be aware. EWTN, Global Catholic Radio Network, hosts a call-in radio show entitled Open Line. A listener called in with a question regarding the allegation that the Catholic Church has changed the Sabbath from Saturday to Sunday.
Madrid stated that the current Saturday is not the original Biblical Sabbath but that the change made by the Catholic Church was actually one of calendation. Following is a transcript of his statements. To listen to Madrid's remarks, click play.
Well, what we have to remember is, first of all what Jesus said: He said don't forget that man was not made for the Sabbath; the Sabbath was made for man. And, the Lord Himself, we're told, was the Lord of the Sabbath, so He had the authority, in areas as far as how we would observe that commandment.
What your brother-in-law may not understand is that the Catholic Church did not change that commandment. The Catholic Church observes the commandment to keep holy the Lo- . . . the Sabbath, but it does so on the Lord's Day, and the earliest Christians transferred their observance of that commandment from Saturday to Sunday.
First of all, because there was a distinct break between the Old Testament requirements: the rituals and Mosaic covenant demands dealing with the Sabbath worship and animal sacrifices, and that sort of thing. And they wanted to show that Christianity was distinct from Judaism. It came from Judaism, but it was distinct from it. Uh, celebrating the Lord's coming, I'm sorry, celebrating the Lord's resurrection and death on the day that He rose from the dead seemed to be the most appropriate.
Uh, the other thing that we should remember, too, is that our calendar that we follow, including Seventh-day Adventists, is not only a calendar that was devised by the Catholic Church, but also it is a calendar that's based upon the solar year, not the lunar year. And the Jewish calendar that was observed in the time of Christ is, follows a lunar calendar, which is several days short of the solar calendar.
So the great irony is that even the Seventh-day Adventists themselves are not worshiping on exactly the same Sabbath day as the Jews of the time of Christ, because it's several days off now, uh, having, uh, switched to [from?] following the lunar calendar.