ACTS 15:1-4

 Q: Is there something in the modern day that we could equate circumcision with? Also, how

 would they know who was circumcised and who was not? I assume they weren’t running around

 naked. It is hard for me to understand the depth that this seems to have to their cultural identity, and

 especially what it has to do with faith. 

 

On your first question, liturgical churches tend to equate circumcision with baptism even though there is

little real NT justification for that idea. On your second question, it is a clearer indication of religion than

with any other religion and actually became important during the Hellenistic Period when athletes would

compete in the nude. In addition would be distinctions in clothing, hair style and dietary habits. On your 

last point, Paul would agree with you. It was intended to be a reminder of the covenant between Israel and

God -- a blood sacrifice in a way. Therefore it was more a sign to the person himself, not to other Jews.