I know a lot of people think that a day of rest belongs to the Old Testament rulebook. But I'm still working that out, since Scripture tells us about a day of rest before the law was given.
Besides, something about doing no work at all is a gift to self.
Your word, O Lord, is eternal; it stands firm in the heavens. Your faithfulness continues through all generations; you established the earth, and it endures. Your laws endure to this day, for all things serve you. If your law had not been my delight, I would have perished in my affliction. I will never forget your precepts, for by them you have preserved my life. Save me for I am yours. I have sought out your precepts. Psalm 119:89-94 NIV
The Lord our God has secrets known to no one. We are not accountable for them, but we and our children are accountable forever for all that he has revealed to us, so that we may obey all the terms of these instructions. Deuteronomy 29:29 NEV