There is a thin strip of grace which we have to traverse all along our spiritual journey. On one side is legalism and on the other is licentiousness. Both are anathema to God. While we strive to please God in everything, we can easily move into initiating something that depends on the flesh. That is the essence of the Law. The Law failed only because Israel relied on the arm of the flesh, and not because it was not good or godly. So, everything we do has to be born out of the Spirit birthing it in us. God did not do away with the Law but it has to be emphazized that we do not fulfil the Law. Instead, it is the Spirit fulfilling it in us and through us, Romans 8:4. A sabbath rest is a good thing until we turn it into a law. The insistence on setting a day aside can be the beginning of a journey into bondage under the Law. Why not a few hours every week? Why not the morning hours? The essence of the sabbath is not the time duration but the rest itself. It is always good to practice spiritual disciplines and God knows we need more of it, but not at the cost of losing our freedom in Christ. Like I said, it is a fine line and when we take a leaf out of the Law and make it compulsory, we always fall into pride and the deception of the enemy. It is the same with tithing or any other principle we take out of the Law. The Law was always meant to be a guideline and never a rule (except for its moral aspect), because we are not under the Law but under grace.