Genesis 17:9-11

Revised Standard Version

⁹ And God said to Abraham, “As for you, you shall keep my covenant, you and your descendants after you throughout their generations. ¹⁰ This is my covenant, which you shall keep, between me and you and your descendants after you: Every male among you shall be circumcised. ¹¹ You shall be circumcised in the flesh of your foreskins, and it shall be a sign of the covenant between me and you.