Genesis 17:11-14

11And 1you shall be circumcised in the flesh of your foreskin, and it shall be the sign of the covenant between Me and you. 12And every male among you who is 2eight days old shall be circumcised throughout your generations, a servant who is born in the house or who is bought with money from any foreigner, who is not of your 3descendants. 13A servant who is born in your house or 4who is bought with your money shall surely be circumcised; thus shall My covenant be in your flesh for an everlasting covenant. 14But an uncircumcised male who is not circumcised in the flesh of his foreskin, that person shall be 5cut off from his people; he has broken My covenant.”