Genesis 17:9-14 NLT

9 "Your part of the agreement," God told Abraham, "is to obey the terms of the covenant. You and all your descendants have this continual responsibility.
10 This is the covenant that you and your descendants must keep: Each male among you must be circumcised;
11 the flesh of his foreskin must be cut off. This will be a sign that you and they have accepted this covenant.
12 Every male child must be circumcised on the eighth day after his birth. This applies not only to members of your family, but also to the servants born in your household and the foreign-born servants whom you have purchased.
13 All must be circumcised. Your bodies will thus bear the mark of my everlasting covenant.
14 Anyone who refuses to be circumcised will be cut off from the covenant family for violating the covenant."