1 Corinthians 7:17-20

Only, as the Lord has assigned to each one, as God has called each, in this manner let him walk. And so I direct in all the churches. Was any man called when he was already circumcised? He is not to become uncircumcised. Has anyone been called in uncircumcision? He is not to be circumcised. Circumcision is nothing, and uncircumcision is nothing, but what matters is the keeping of the commandments of God. Each man must remain in that condition in which he was called.