How does the Old Testament relate to the New Testament? How does the Christian Church relate to Israel? Do Christians have to keep the Old Testament laws?
These are some questions that all Christians ponder. But we don't all come to the same conclusions. Some Christians emphasise the similarities between the Old Testament and the New. This is known as a theology based on Continuity. And other Christians take note of all the changes that we find in the New Testament and favour a theology of Discontinuity.
But, all of us have elements of Continuity and Discontinuity in our theology, because this is forced on us by the bible itself.
The Covenant Theology of Presbyterians and Anglicans tends to emphasise the Continuity between the Old and New Covenants, and it is this favouring of continuity which leads them to teach that infants should be baptised.
The Dispensationalist Theology of others, including some Baptists and some Pentecostals emphasises the differences in the covenants and is part of the reason why they only want to baptise believers.
New Covenant Theology is intended to be a via media between the above 2 systems. It is Reformed, like Covenant Theology, but emphasises differences in Christ's New Covenant not brought out by Presbyterians and Anglicans. Although the terminology is somewhat new, it is close to the teaching of John Bunyan and also the writings of Don Carson and Douglas Moo, who were prepared to write commendations of Zaspel and Wells' book New Covenant Theology, while not wanting their theology to be given this label.
Steve Lehrer's new book New Covenant Theology: questions answered builds on the excellent work done by Fred Zaspel and Tom Wells.