Romans 4:11-12 NIV

[11] And he received circumcision as a sign, a seal of the righteousness that he had by faith while he was still uncircumcised. So then, he is the father of all who believe but have not been circumcised, in order that righteousness might be credited to them. [12] And he is then also the father of the circumcised who not only are circumcised but who also follow in the footsteps of the faith that our father Abraham had before he was circumcised.