Now isn't that convenient???
Christ came to do away with all that. The Apostle is simply saying that we’re not justified by being Jew but are justified by being Christian.
If salvation is based on "merit," then the chrstian religion isn't necessary. There was already a religion, indisputably from G-d Himself, that had "works" and rituals and ceremonies and laws. The very idea that "faith vs. works" boils down to the old (Biblical) religion vs. the new (post-Biblical) religion is the height of hypocrisy. This argument is essentially Protestant and chrstianity brought Protestantism on itself by fulminating against G-d given laws while insisting on man-made laws.
Just desserts.