Ezekiel 20:12, 20
Ezekiel 20:12 ASV
Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am Jehovah that sanctifieth them.
Ezekiel 20:20 ASV
and hallow my sabbaths; and they shall be a sign between me and you, that ye may know that I am Jehovah your God.