How does Law Sabbath differ from Grace Sabbath?

They are one and the same Biblically, the Seventh-day of the week, Saturday. We enter this rest by faith through grace. All obedience is by faith through grace, focusing on Jesus. But still people take their attention off of Christ and then they sin, trasgressing the law. If you conduct your own work or pleasure on the Sabbath, you are sinning, not entering Christ's rest.