A central theme in Dumbrell's writings has been "covenant", especially the "new covenant". In a forthcoming article on Gen. 6.18 and Lk. 22.20, Dumbrell writes this:
"All this means that God's in-breaking salvation through Jesus, the cross and the resurrection, provides for eventual fulfilment of the Abrahamic covenant (Luke 1:72-75), and in turn leads to the fulfilment of God's total purposes for creation, which was what the Sinai Covenant was designed to effect, and would have done so had Israel seen it as a way for her to have lived as God's people. W.Foerster [TDNT 7.990-01] notes that salvation, kingdom of God, messianic jubilee, and New Covenant, are overlapping descriptions with only slightly different nuances."
Bill Dumbrell's works have several distinct strengths:
1. He takes seriously the Old Testament background of the New Testament.
2. Covenant is one of the basic building blocks of God's relationship with Israel and it carries over in some way into the new covenant era.
3. In Paul's thought, the relationship between the Abrahamic, Mosaic, and New Covenants was a central issue underpinning much of his exegesis of biblical texts and appearing in his argumentation against those who would try to proselytize his Gentile churches.
4. The correlation between the concepts of Kingdom and Covenant is helpful and accurate (Max Turner and Vincent Taylor say similar things on this point too).
At the same time, I often wonder if Dumbrell overplays the covenantal card at certain points. For instance in his reading of Gal. 2.15-21 (see his European Journal of Theology article and his Galatians commentary) I think he gives too much attention to justification as "covenant membership". I think justification is more comprehensive than this in Paul's thought and it has both horizontal and vertical elements. Secondly, the word "covenant" is very rare in the NT and when it does appear it is ordinarily in the context of discontinuity, e.g. 2 Corinthians 3 and Romans 9 (it pains me to say it, but that is one observation where the dispies are actually right!). Thirdly, I think it worthwhile to consider James Dunn's proposal that Paul has a theology of "promise" rather than a theology of "covenant" per se, esp. in Romans 9-11.
Otherwise, Bill Dumbrell has written two recent commentaries on Galatians and John which are worth knowing about and, if you like biblical theology, worth reading.
His volume, Galatians: A New Covenant Commentary is a precis of much of this thought on Paul and covenant. Here is one interesting quote: "The New Covenant in operation would permit the fulfilment of Israel's commission under the Sinai Covenant to implement the Abrahamic covenant in a way which was prevented by Israel's disobedience in the Old Testament. The New Covenant would facilitate a restored, obedient Israel, brought into being in Acts 2, to fulfil its commission imposed by virtue of its election as the people of God (Exod 19:5-6). That commission was for Israel a charge to be the light to the world, to bring about final world change and the full implementation of the kingdom of God. What the New Covenant would mean for an obedient restored Israel in the post-cross era, was world mission. We are no longer operating from Pentecost onwards in terms of Jerusalem as a world centre to which Gentiles will come in submision and obedience. The Promised Land is the now the world itself, now begun in Christian evidence to be seen as a type of the final antitype of the New Creation (p. vi)."
My thanks to Bill Dumbrell for sending me copies!