Justifying the ungodly
God, according to Romans 4:5, "justifies the ungodly". There are, as always, many ways this phrase could be read depending on how the key words are interpreted.
The most common Protestant reading would be to take justifies in a legal sense and ungodly in a moral sense, resulting in a reading that God "declares righteous the immoral". Catholics however would generally read both words in a moral sense, resulting in a reading where God "makes the immoral righteous".
New Perspective scholars however seem to almost universally agree that the phrases "Gentile sinners" and "ungodly Gentiles" are proverbial phrases within Judaism of this time. Therefore the term "sinner" or "ungodly" can and does often simply mean "Gentile" or "person who doesn't follow the Mosaic Law", rather than indicating an immoral or wicked person. It has an ethnic/legal meaning rather than moral meaning.
Thus the NPP reading is that God "declares righteous those who do not follow the Mosaic Law". This seems to me to be the best reading and agree with the context in which Paul talks about how Abraham was declared righteous by God before he was circumcised.