I am opening this thread because a member,
@JesusFan , seems fascinated with the NPP but at the same time confuses the "classic view" of Atonement with the NPP.
I figure others here more knowledgeable than I may be able to help him. I know some of the NPP, but the topic has not really sparked my interest as it seems problematic at the start.
The New Perspective on Paul (NPP) is a movement (with many different views) focused on the writings on Paul. The NPP is primarily associated with E.P. Sanders and James Dunn (Krister Stendahl in the 1960's, prior to Sanders).
The primary idea is that the Reformers read their situation with the Catholic Church into Paul's use of works - that Paul's use of "works" primarily referred to works of the Law rather than general Christian works or good behavior.
This changes things a bit. The idea is that we are justified by faith rather than works of the Law, but that this faith produces works in the present which points to a future justification.
Personally I think the NPP gets somewhat too much in the weeds and does not come out very coherently. I agree that Paul often used "works" to mean "works of the Law", but at the same time this seems (IMHO) to assume a Jewish audience. I think the simple truth is we do not earn salvation, but that good works accompany salvation.
So good works can be a sign of a future justification (at the day of Judgment) but they are fruits of a present justification (salvation, justified in Christ).