The Deuteronomy reason for Sabbath-keeping is that our ancestors in Egypt went four hundred years without a vacation (Deut. 5:15). Never a day off. The consequence: they were no longer considered persons but slaves. Hands. Work units. Not persons created in the image of God but equipment for making bricks and building pyramids. Humanity was defaced.
Lest any of us do that to our neighbour or husband or wife or child or employee, we are commanded to keep a sabbath. The moment we begin to see others in terms of what they can do rather and who they are, we mutilate humanity and violate community. It is no use claiming “I don’t need to rest this week and therefore will not keep a sabbath” — our lives are so interconnected that we inevitably involve others in our work whether we intend it or not. Sabbath-keeping is elemental kindness. Sabbath-keeping is commanded to preserve the image of God in our neighbours so that we see them as they are, not as we need them or want them.
From Working the Angles: The Shape of Pastoral Integrity by Eugene Peterson