1 Corinthians 7:19-21

Circumcision is nothing, and uncircumcision is nothing, but what matters is keeping the commandments of God. Each one should remain in the condition in which he was [when he was] called. Were you a slave when you were called? Do not worry about that [since your status as a believer is equal to that of a freeborn believer]; but if you are able to gain your freedom, do that.