Romans 4:10-11
4:10 How then was it credited to him? Was he circumcised at the time, or not? No, he was not circumcised but uncircumcised!
4:11 And he received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised, so that he would become the father of all those who believe but have never been circumcised, that they too could have righteousness credited to them.