In Counted Righteous in Christ (going forward CRC) John Piper says, “The doctrine of justification is the eye of more than one storm” (42). In associated footnote Piper expounds,

Three of the major storms, worthy of attention but not treated here, include (1) ecumenical dialogues on Evangelical and Catholic doctrine; (2) the so-called “New Perspective” on Paul and the law; and (3) the relationship of faith and obedience, specifically the conflation of faith and works of faith as the instrument of justification. . . . In my view, a detailed defense still needs to be done on the historic Protestant view of the relationship between faith and obedience, so that the two are not conflated in the instrument of justification, as many in the biblical-theological circles are doing these days. (See note 35 of Chapter Three of this book.) Perhaps, if the Lord should grant time and energy, I will take up this subject in another short book.

John Piper is attempting to provide a historic Protestant response to men like Robert H. Gundry — who is merely a representative of “many in the biblical-theological circles” (mentioned above). It is Gundry who argued in a series of Books and Culture issues in 2001 (here and here) that “the doctrine that Christ’s righteousness is imputed to believing sinners needs to be abandoned.” “That doctrine of imputation is not even biblical. Still less is it essential to the Gospel” (CRC, 44).

Piper continues to elaborate on this recent surge. He says,

But there is even more to the challenge. Not only does Gundry regard as unbiblical any positive imputation of divine righteousness to believers, he also says that our faith itself is our righteousness, because God counts it to be such. [Piper begins quoting Gundry] “Since faith as distinct from works is credited as righteousness, the righteousness of faith is a righteousness that by God’s reckoning consists of faith even though faith is not itself a work” [emphasis added by Piper]. But this “righteousness”–this faith–is not imputed to us, but really is our righteousness in that we respond to God in faith (by grace) and God counts our faith to be what it is–righteousness (CRC, 46).

John Piper in an attempt to be fair and charitable elaborates on Gundry’s position in associated footnote. He says,

This should not be taken to mean that Gundry believes that faith is, in and of itself, righteousness by its nature. In personal correspondence (02-04-02, quoted with permission), Gundry writes: “. . . I myself would rather say that God counts faith as righteousness even though it isn’t righteousness in the sense of a performed work. Just as God regards believers as righteous even though they’re sinners, he also regards their faith as righteousness even though it’s opposite a work of moral rectitude.”

In Chapter Three John Piper provides the necessary biblical exegesis to show that “Gundry’s arguments do not overthrow the traditional Protestant understanding of Scripture that finds in justification the imputation of divine righteousness and a clear and necessary distinction between this act and God’s subsequent and necessary work of sanctification” (CRC, 80).