The Most Venerable Sabbath
It must be remembered that the Sabbath, though a world-aged observance, has passed through the various phases of the development of redemption, remaining the same in essence but modified as to its form, as the new state of affairs at each point might require. The Sabbath is not only the most venerable, it is likewise the most living of all the sacramental realities of our religion. It has faithfully accompanied the people of God on their march through the ages.
Geerhardus Vos, Biblical Theology: Old and New Testaments (Eugene, OR: Wipf and Stock Publishers, 2003), 139.