Listen now | From the audiobook Explanation of Catholic Morals - Chapter 49, "The Day of Rest," examines the designation of one day in seven for rest, noting various natural and symbolic reasons for the number seven, though ultimately affirming that the sole, sufficient reason is the positive will of God. The chapter then directly confronts the shift from the Mosaic Sabbath (Saturday) to Sunday observance in Christianity, particularly challenging Protestants to justify this change based on their "Bible alone" principle. It argues that Scripture does not explicitly authorize this change, even with Christ's resurrection on Sunday, concluding that the only legitimate authority for this change is the Holy Roman Catholic Church and its tradition, as the interpreter of God's word. This presents a logical dilemma for Protestants, who, if consistent, must either return to the Jewish Sabbath or acknowledge the Church's authority, which they otherwise often reject.