[Phil 3:4-6] is a statement of personal confidence indeed, but the confidence is not primarily, if at all of personal achievement. It is rather, once again, the confidence of Paul as a member of Israel, the covenant people--confident in his ethnic identity, confident in his share in the covenant marked by circumcision, confident that he was living within the terms of the covenant as laid out in the law, confident not least that he was defending the distinctiveness of Israel and its separateness from the nations.
--James Dunn, The New Perspective on Paul (Eerdmans 2008), 374, in a 1997 essay
[In Phil 3:5] we move beyond question of confidence in ethnic identity to confidence in the extra commitment he had chosen to make by becoming a Pharisee. . . . [Phil 3:6] is now well beyond confidence in ethnic status. There is at least an element of self-achievement and of pride in self-achievement in both Gal 1:14 and Phil 3:6.
--James Dunn, The New Perspective on Paul (Eerdmans 2008), 478, 480, in a 2008 essay
It is not hard to see why D. A. Carson called Dunn's work 'historical revisionism' in Carson's 2005 lectures on the New Perspective at RTS.