Genesis 17:10

17:10 This is my requirement that you and your descendants after you must keep: Every male among you must be circumcised.

Exodus 12:13

12:13 The blood will be a sign for you on the houses where you are, so that when I see the blood I will pass over you, and this plague will not fall on you to destroy you when I attack the land of Egypt.

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.

Exodus 31:17

31:17 It is a sign between me and the Israelites forever; for in six days the Lord made the heavens and the earth, and on the seventh day he rested and was refreshed.’”

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.”