1 Corinthians 7:18-20

For instance, a man who was circumcised before he became a believer should not try to reverse it. And the man who was uncircumcised when he became a believer should not be circumcised now. For it makes no difference whether or not a man has been circumcised. The important thing is to keep God’s commandments. Yes, each of you should remain as you were when God called you.