Genesis 17:12-14

12Every male among you who is eight days old shall be circumcised throughout your generations, [including] a servant whether born in the house or one who is purchased with [your] money from any foreigner, who is not of your descendants.

13A servant who is born in your house or one who is purchased with your money must be circumcised; and [the sign of] My covenant shall be in your flesh for an everlasting covenant.

14And the male who is not circumcised in the flesh of his foreskin, that person shall be cut off from his people; he has broken My covenant.”