Genesis 17:9-11

American Standard Version

⁹ And God said unto Abraham, And as for thee, thou shalt keep my covenant, thou, and thy seed after thee throughout their generations. ¹⁰ This is my covenant, which ye shall keep, between me and you and thy seed after thee: every male among you shall be circumcised. ¹¹ And ye shall be circumcised in the flesh of your foreskin; and it shall be a token of a covenant betwixt me and you.