"The New Perspective on Paul is a trend or an idea that has been around especially since the late 1970's in academic circles, but in the last 10 years it has been making its way into popular preaching which says that we need to understand Paul different especially in the areas of the doctrine of justification and the doctrine of the church. We need to understand Paul differently than Christians have in the past, especially those Christians who have been reliant upon Martin Luther and John Calvin and the classic Protestant Reformers' articulation of what Paul was teaching about justification.
To boil it down, the New Perspective says that when the Apostle Paul was talking about justification by faith, he was not talking about liberating Jewish people from a legalistic view of salvation by self effort, but that he was articulating a view of what it meant to be a part of the people of God which was ethnically inclusive, and which rejected some of the boundary markers and the moral ceremonial practices of the old Hebrew religion. That's a pretty comprehensive change from the classic Protestant understanding of justification by faith."
Listen to the full interview here.