There is a subordinate theme of racism at play here as well.  The Judaizers, while admitting that Gentiles could be saved,  wanted to have authority and take leadership in the new churches.  They claimed the heritage of Israel, they were fellow citizens of the Messiah, they had 1500 years of history worshipping God the Father.  They knew the lingo -- holiness, purity, righteousness, sin, covenant, and so on.  They thought they had a right and a responsibility to tutor the Gentiles, who were but babes in the spirit, lately idolaters.  It is possible that their attitude was similar to that of 19th Century white colonizers who felt they had an obligation to uplift the rest of humanity -- it was the "white man's burden" to impart civilization to the non-white races. The Jews felt they had a similar spiritual mission to mankind. 

          

But Paul not only rejected their superiority, he believed they needed to be converted to a true righteousness based not on their knowledge and tradition, but on God's gift to all men in Jesus Christ.  Instead of pride, these believing Jews ought to have expressed a humility that recognized their true spiritual condition: the Gentiles were not the only people who stood in need of divine mercy.  This is why Paul so vehemently despised all the many symbols of a false spirituality that the Judaizers cherished: circumcision, good family, title or membership in an exclusive group, zealous adherence to the Law, etc.  God had saved Paul not because of all this claptrap, but in spite of it.

          

It is not just the Biblical Judaizers who put so much emphasis on ethnicity and cultural heritage.  Comparative ethnicity is THE distinctive feature of modern politics and secular education.  What is it that gives a person his value, self-esteem and uniqueness? --  the answer is race, nationality, language, caste or class.  This is the gospel of multi-culturalism, and it rules the day.  It also divides humanity into countless competing groups and sub-groups, all based on biology, genealogy or geographical proximity.  This ideology is profoundly anti-democratic and anti-spiritual, and represents a resurgence of racism with a "benevolent" face.  If the most significant aspect of a person's identity is his nationality or ethnicity, then his spirit is suppressed or denied.  This is why a Christian approach to race relations has to be different than that of a secular person, because the latter has no understanding that spiritual unity in Christ cancels out all racial and cultural barriers.