Romans 4:10
[But] when was he given credit [i.e., for being righteous]? Was it after he was circumcised, or before? It was before he was circumcised, not afterward.
1 Corinthians 7:18-19
Was any man already circumcised when he was called [by God to be a Christian]? Then he should not [try to] become uncircumcised. [Note: Some Jews in that day resorted to a surgical procedure in an attempt to conceal their circumcision]. Was any man uncircumcised when he was called? Then he should not become circumcised.
Galatians 5:6
For in [our relationship with] Christ neither the practice of circumcision nor refraining from its practice matters in any way; but [all that really matters is having a genuine] faith [in Christ] that causes us to work [for Him] out of a genuine love [for Him and others].
Galatians 6:15
For it does not matter whether a person practices circumcision or refrains from practicing it; what really matters is [whether or not he is] a new creature [in the eyes of God].