Why the Sabbath is Sunday

"The Apostles, therefore, resolved to consecrate the first of the seven days of the week to the divine worship, and they called it 'the Lord's Day.' St. John makes mention of 'the Lord's Day' in the Apocalypse (i. 10), and St. Paul commands collections to be made 'on the first day of the week' (I Cor., xvi. 2). . . . From all this we learn that even then the Lord's Day was kept holy in the Church. . . . The Church of God has thought it well to transfer the celebration and observance of the Sabbath to Sunday. On that day light first shone on the world when the Lord arose on that day, and the gate of eternal life was thrown open to us and we were called out of darkness into light. . . . We also learn from the Holy Scriptures that the first day of the week was held sacred for other reasons, viz., on that day the creation began, and on that day the Holy Ghost descended upon the Apostles" ("Roman Catechism." Third Commandment, 7, 18).