Genesis 17:12-13
Genesis 17:12-13 RSVCI
He that is eight days old among you shall be circumcised; every male throughout your generations, whether born in your house, or bought with your money from any foreigner who is not of your offspring, both he that is born in your house and he that is bought with your money, shall be circumcised. So shall my covenant be in your flesh an everlasting covenant.