Chapter 26 — Part III: The Decalogue — The Third Commandment
Section 19. "Keep Holy" — In the Scriptures keeping holy the Sabbath means a cessation from bodily labor and from business, as is clear from the following words of the Commandment: Thou shalt do no work on it. But this is not all that it means; otherwise it would have been sufficient to say in Deuteronomy, Observe the day of the sabbath; but it is added, and sanctify it; and these additional words prove that the Sabbath is a day sacred to religion, set apart for works of piety and devotion.