Philippians and Pharisees

I’m not sure why it never struck me before, but I just recently realized that Paul’s mention in Philippians about his being or having been a Pharisee ought to get more attention. Paul assumes that the Philippians know what a Pharisee is. Perhaps we can assume that he told them on some previous occasion. But it might also hint at two other possibilities – that he assumed they knew stories about the Pharisees and Jesus such as would appear later in the Gospels, or otherwise the Pharisees were much more widely known than we otherwise have evidence for in Jewish sources. Either would be significant!