1 Corinthians 7:19

Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God (KJV)

Then: Oops. The Jews in Corinth just hit a conundrom, but Paul ignores it. Keeping the commandments is a top priority for Jews and new followers of Christ alike. Paul's focus is on the end game, Christ as the fulfillment of the Law. From days of the Old Covenant, circumcision was required. In the days of the New Covenant, the sign of faithfulness and commitment signified by circumcision is no longer important. Accepting Christ as the Son, an integral, inseparable part of God supreme and the one way to salvation has top priority. After that, all other aspects of obedience fall into place. Paul skips the explanation (although discussing it in Romans) and keeps pursuing answers to the Corinthians' questions.

Now: If you find the KJV hard to read, substitute "what's really important is" for the word "but." That's the essence of N. T. Wright's translation (p. 84). During World War II, Hitler used circumcision to identify Jews. He was astounded to learn that many Western Christians were circumcised too. Currently, there is a push to completely eliminate the practice. The mantra is that the procedure does cause pain to seven-day old infants and is not effective in preventing diseases. Some may suspect an underlying agenda of devaluing Christian beliefs. That can not happen if today's believers lock in to Paul's teachings: Love Christ, know Christ, serve Christ, teach Christ. That's the alpha and omega of being a Christian.