Genesis 17:8-10

17:8 I will give the whole land of Canaan – the land where you are now residing – to you and your descendants after you as a permanent possession. I will be their God.”

17:9 Then God said to Abraham, “As for you, you must keep the covenantal requirement I am imposing on you and your descendants after you throughout their generations. 17:10 This is my requirement that you and your descendants after you must keep: Every male among you must be circumcised.