Ezekiel 20:12, 20-21

Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am the LORD that sanctify them.

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 the children rebelled against me: they walked not in my statutes, neither kept my judgments to do them, which if a man do, he shall even live in them; they polluted my sabbaths: then I said, I would pour out my fury upon them, to accomplish my anger against them in the wilderness.