Davies later returned to Duke as George Washington Ivey Professor of Advanced Studies and Research in Christian Origins.

His books on Paul's writings and on the Sermon on the Mount (in Matthew) explore Pharisaic understandings of the Law (or Torah) in the "age to come" or messianic era – against the backdrop of developments and thought in Judaism not only during the time of Jesus but also in the closing decades of the first century (especially the destruction of Jerusalem and the Council of Jamnia).

In The Setting of the Sermon on the Mount (1964), Davies sees a law which remains even under the covenant of grace and thus spans the canonical tensions between James and Paul.

Theologically, then, by reorienting views on Paul, and by bringing Pharisaic, nomistic themes in Matthew to the fore, Davies sought to pull together the various New Testament strands and aims at a comprehensive combination of Law and Gospel.

By no means are the two in agreement on all things, but Davies's work in de-Hellenizing Paul allowed for Sanders to approach the apostle dusted, scrubbed, and ready for fresh analysis.