"If this meal with friends and family is rich, how much more the banquet of the great King? If resting in this patch of sunlight is refreshing, how much more to rest in that place where God and the Lamb shine brighter than any sun? ...Take anything you delight in here on earth... Enjoy them all. Find rest in them. But imagine how much more awaits you." ~Mark Buchanan
C.S. Lewis has this beautiful metaphor of life here on earth that's always been my favorite: the shadowlands. You and I live in the reality of things yet to be... pilgrims wondering through the shadows to a greater resting place... heaven. You and I were not meant to take up residency in the shadowlands. We were not made for it, and our restlessness whispers it in our hearts. We all have a small sense of restlessness in us... searching for some perfect place to grow our roots... our heaven here on earth. But it's not here. We will never find it while roaming on earth. For all that the earth offers to us our shadows, and true to the nature of these shadows they lead and point to something greater. That was and will always be their purpose. God created shadows to merely mirror or echo something greater... Him.
"God let's us groan now to woo us heavenward. He gives us rest here, but not enough to fully satisfy, just enough to keep us in the race. With rest he mixes restlessness... Like a wisteria plant, our restlessness needs to be trained to go in a certain direction..." ~Mark Buchanan
As much as Sabbath is a gift to us to enjoy and delight in, this too was fractured at the fall. For on this side of heaven you and I will never be able to enter into perfect rest while sin lingers around us. Sabbath is a form of a shadow itself now, pointing to the day when we can inhabit the perfect, complete rest... in heaven. Practicing Sabbath while on earth is rehearsing for when we'll celebrate it in heaven perfectly.