Steve,
     For Israel, they were to take a certain % of their increase to give to the LORD & the rest was for themselves. In a similar fashion, one day of the week was to be kept holy unto the LORD, the sabbath, and six days were profane & for their own use.
     For the Christian, everyday should be equally holy unto the LORD. In our case, all that we do, should be holy unto the LORD, work, rest, eating, praying, etc. The key for us is not in working or resting, but rather that all we do should be heartily unto the LORD. For us, a day of rest, or a day of work, should both be holy & unto the LORD. So, whether we eat or sleep, fast or wake, work or rest, it should all be done in the name of the LORD Jesus, and all of it should be holy unto him.
    So in this sense, it is not legalism, as we cannot possibly live this way by our power or sheer determination of our wills, but only in the power of the Holy Ghost. When we walk in the Spirit, he only does right. However, when we walk in the flesh, even if we dot all our I's & cross all our T's, on the outside, our motives are still sinful in our hearts.
The Holy Ghost, who inspired the books of the law, will not break the law, as he is holy & perfect, and all he does is in agreement with what he inspired. So, when we walk in the Spirit, it is he that is doing right in us, and it too will be in accordance with the scriptures. However, when we "try" to live in accordance with the scriptures, then it is us, and not him, "trying", therefore it is not perfect or holy, it is actually pride, and thus sinful & in the flesh.
      Gino