Sorry, the title to this post is some old humor about circumcision. While 4:4-8 could be seen as the show-stopper for the New Perspective, 4:9 actually turns the lights on for its show. How so? Because, after positing a “faith” vs. a “reckoning” system, Paul turns the lights once again on Jewish privilege.
Here’s his question: Is this blessedness (that extended to Abraham and David) for the circumcised or also for the uncircumcised? Which means: Is the blessing of God for one nation, those who are the fleshly descendants of Abraham, or is the blessing for all? Since his readers will say “for all,” Paul nows shows why.

Why? Because Abraham got that blessing when he believed. Circumcision did not come along until afterwards, and it was only a “seal” of the “faith” that Abraham already had. Which means that Abraham has to be seen as a “believer” (one with “faith”) rather than a “law-doer” (which is what focusing on circumcision will get you). The people of God are those who descend from Abraham’s faith not from Abraham’s circumcision, and that means “all.”
The question of 4:9 is very important, for it shows that Paul’s concern is with Jewish privilege and not simply assertion of self via obedience of the Torah or merit.
Tomorrow, 4:13-15, as we work through N.T. Wright’s commentary on Romans.,
Notice what Paul says in 4:14: “If it is the adherents of the law how are to be heirs, faith is null and the promise is void.” Why? Because faith and promise are found in Genesis 12 and 15, well before circumcision (Law), which comes up in Genesis 17.
Even more, this shows that Abraham was “justified” while still uncircumcised, showing they are two independent things. Faith, blessings, and justification are independent of circumcision. Therefore, the blessing is not only for the circumcised but for everyone who believes (as did Abraham).
Circumcision, then, points toward faith and covenant membership by faith.