When one jettisons the concept of the Covenant of Works, inevitably some form of unorthodoxy will come up. The denial of the plain reading of Rom. 2 probably serves as the best illustration, with peoples and movements as diverse as John Piper, the FV (Federal Vision) and NPP (New Perspective on Paul) coming up with their strange ideas of what they think Rom. 2 actually teaches. For Piper, it is the idea of "Future Grace", a concept which is self-contradictory at best, and borders on serious error at worst. In the case of the FVers, obedience is a work that does indeed saves — that "truly responding to the Law (the Word) in faith does justify" (Schlissel, 260), as the review in the Trinity Review quotes.
In this blog post, WSC grad Joshua Martin briefly addresses the text of Rom. 2:13 in context and show what is the true teaching of this verse over and against the mangled interpretations offered by others. As Martin states:
Some find in this verse the doctrine of justification by works plus faith, while others – rightly insisting that justification is by faith alone (Rom 3:28, et al.) – understand the Apostle to be speaking of works as the fruit of faith (i.e. justification is by faith alone, but that faith is never alone in the person justified.). Both approaches miss the Apostle Paul’s point entirely.
... Paul is not here discussing the relationship of works and saving faith. He approaches this subject in chapters 6 and 7. His topic is the condemnation of the law and verse 13 does not represent a parenthetical comment on another subject, but it is rather the crux of the matter.
At last we arrive at verse 13 where Paul argues that it is the “doers of the law who will be justified.” Paul’s point here is not to safeguard the doctrine of justification by faith from the error of antinomianism. Paul has not even mentioned justification by faith! He does not even begin to address the gospel in general, the atonement of Christ, or justification by faith until the pivotal point in chapter three.
It seems that many people need to be taught how to read the Bible in sequence, and to be reminded that chapter 2 is to be read after chapter 1, and verse 20 after verse 19. The Bible is not a cookbook or life manual or a reference book of doctrinal formula or anything else, but it is written to be read in the way it is written - sequentially chapter by chapter, verse by verse. This is incidentally why expository preaching is the best method for revealing to God's people what God has actually said in His Word, as such is more conducive for bringing out the truths in God's Word and allow the Spirit to speak to us without the interference of men. The preacher is to be God's instrument so that the Spirit can speak to us through the Word preached, not to be philosophers offering their "theological" opinions and lessons in moralism and as such obscure the plain teachings in God's holy, authoritative and perspicuous Word.