Longer Catechism (Orthodox) 26.538

Chapter 26 — Part III — The Ten Commandments

Section 538. Q. How, then, does the Christian Church obey the fourth commandment? A. She still to every six days keeps a seventh, only not the last of the seven days, which is the Sabbath, but the first day in every week, which is the Day of the Resurrection, or lord's Day.