Genesis 17:11-13

Complete Jewish Bible

¹¹ You are to be circumcised in the flesh of your foreskin; this will be the sign of the covenant between me and you. ¹² Generation after generation, every male among you who is eight days old is to be circumcised, including slaves born within your household and those bought from a foreigner not descended from you. ¹³ The slave born in your house and the person bought with your money must be circumcised; thus my covenant will be in your flesh as an everlasting covenant.