9 Cometh this blessedness then upon the circumcision only, or upon the uncircumcision also? for we say that faith was reckoned to Abraham for righteousness.
10 How was it then reckoned? when he was in circumcision, or in uncircumcision? Not in circumcision, but in uncircumcision. 11 And he received the sign of circumcision, a seal of the righteousness of the faith which he had yet being uncircumcised: that he might be the father of all them that believe, though they be not circumcised; that righteousness might be imputed unto them also:
Circumcision has never been a matter of justification. It was not salvation for Abraham, Moses, David, Jeremiah, Y'shua, Paul; nor is it salvation for any of us. Saul never taught against circumcision, in fact he calls it the seal of righteousness by faith. The issue was conversion to Judaism, which was finalized by circumcision. Which, as you have stated, is not necessary or encouraged or needed.