Romans 4:10-12

How, then, was it judged? when he had circumcision, or when he had it not? Not when he had it, but when he did not have it: And he was given the sign of circumcision as a witness of the faith which he had before he underwent circumcision: so that he might be the father of all those who have faith, though they have not circumcision, and so that righteousness might be put to their account; And the father of circumcision to those who not only are of the circumcision, but who keep to the way of that faith which our father Abraham had before he underwent circumcision.