Romans 4:11-12

Riverside(i) 11 And he received the sign of circumcision as a seal of the righteousness of faith that he had in uncircumcision, so that he should be the father of all who believe while uncircumcised, and righteousness should be credited to them; 12 and the father of the circumcised, that is, of those who are not only circumcised, but who walk in the steps of the faith which our father Abraham had while uncircumcised.