1 Corinthians 7:18, Every Man According As He is Called
The converted Jew should not be ashamed of his Jewish background. His circumcision does not impede his Christian testimony at all. He should accept his past for who he is and rejoice now for what God has done for him in Christ. Likewise, the heathen man who is converted need not follow the Jewish ceremonial law of being circumcised to be accepted into the Christian community. Although salvation begins with the Jews it must by no means be construed that the ceremonial law of circumcision has been carried over to the Christian faith. The Christian is baptised by water as an outward sign of his inward faith. He need not be circumcised following the Jewish ceremonial law. It has been abrogated in Christ.