Sabbaths were Instituted on Account of the People's Sins, and not for a Work of Righteousness.
"Moreover, that God enjoined you to keep the Sabbath, and impose on you other precepts for a sign, as I have already said, on account of your unrighteousness, and that of your fathers, -- as He declares that for the sake of the nations, lest His name be profaned among them, therefore He permitted some of you to remain alive, -- these words of His can prove to you: they are narrated by Ezekiel thus: I am the Lord your God; walk in My statutes, and keep My judgments, and take no part in the customs of Egypt; and hallow My Sabbaths; and they shall be a sign between Me and you, that ye may know that I am the Lord your God. Notwithstanding ye rebelled against Me, and your children walked not in My statutes, neither kept My judgments to do them: which if a man do, he shall live in them. But they polluted My Sabbaths. And I said that I would pour out My fury upon them in the wilderness, to accomplish My anger upon them; yet I did it not; that My name might not be altogether profaned in the sight of the heathen. I led them out before their eyes, and I lifted up Mine hand unto them in the wilderness, that I would scatter them among the heathen, and disperse them through the countries; because they had not executed My judgments, but had despised My statutes, and polluted My Sabbaths, and their eyes were after the devices of their fathers. Wherefore I gave them also statutes which were not good, and judgments whereby they shall not live. And I shall pollute them in their own gifts, that I may destroy all that openeth the womb, when I pass through them.'