Book of Jubilees 15:11
Then the Lord said to Abraham: ‘As for you, keep my covenant — you and your descendants after you. Circumcise all your males; circumcise your foreskins. It will be a sign of my eternal pact (which is) between me and you.
Then the Lord said to Abraham: ‘As for you, keep my covenant — you and your descendants after you. Circumcise all your males; circumcise your foreskins. It will be a sign of my eternal pact (which is) between me and you.