Exodus 31:13

31:13 “Tell the Israelites, ‘Surely you must keep my Sabbaths, for it is a sign between me and you throughout your generations, that you may know that I am the Lord who sanctifies you.

Ezekiel 20:12

20:12 I also gave them my Sabbaths as a reminder of our relationship, so that they would know that I, the Lord, sanctify them.

Ezekiel 20:20

20:20 Treat my Sabbaths as holy and they will be a reminder of our relationship, and then you will know that I am the Lord your God.”