What is covenant theology?
Ligon Duncan writes: "Covenant theology is the Gospel set in the context of God’s eternal plan of communion with his people, and its historical outworking in the covenants of works and grace (as well as in the various progressive stages of the covenant of grace)."
J. I. Packer writes: "The straightforward, if provocative answer to that question is that it is what is nowadays called a hermeneutic -- that is, a way of reading the whole Bible that is itself part of the overall interpretation of the Bible that it undergirds. A successful hermeneutic is a consistent interpretative procedure yielding a consistent understanding of Scripture in turn confirms the propriety of the procedure itself. Covenant theology is a case in point. It is a hermeneutic that forces itself upon every thoughtful Bible-reader who gets to the place, first, of reading, hearing, and digesting Holy Scripture as didactic instruction given through human agents by God himself, in person; second, of recognizing that what the God who speaks the Scriptures tells us about in their pages is his own sustained sovereign action in creation, providence, and grace; third, of discerning that in our salvation by grace God stands revealed as Father, Son and Holy Spirit, executing in tripersonal unity a single cooperative enterprise of raising sinners from the gutter of spiritual destitution to share Christ's glory for ever; and, fourth, of seeing that God-centered thought and life, springing responsively from a God-wrought change of heart that expresses itself spontaneously in grateful praise, is the essence of true knowledge of God. Once Christians have got this far, the covenant theology of the Scriptures is something that they can hardly miss.
If it's something that can hardly be missed, why do so many miss it?
Packer responds: "Yet in one sense they can miss it: that is, by failing to focus on it, even when in general terms they are aware of its reality. God's covenant of grace in Scripture is one of those things that are too big to be easily seen, particularly when one's mind is programmed to look at something smaller. If you are hunting on a map of the Pacific for a particular Polynesian island, your eye will catch dozens of island names, however small they are printed, but the chances are you will never notice the large letters spelling PACIFIC OCEAN that straddle the map completely. Similarly, we may, and I think often do, study such realities as God's promises; faith: the plan of salvation; Jesus Christ the God-man, our prophet, priest and king; the church in both testaments, along with circumcision, passover, baptism, the Lord's Supper, the intricacies of Old Testament worship and the simplicities of its New Testament counterpart; the work of the Holy Spirit in believers; the nature and standards of Christian obedience in holiness and neighbour-love; prayer and communion with God: and many more such themes, without noticing that these relational realities are all covenantal in their very essence. As each Polynesian island is anchored in the Pacific, so each of the matters just mentioned is anchored in God's resolve to relate to his human creatures, and have us relate to him, in covenant -- which means, in the final analysis, a way for man to relate to God that reflects facets of the fellowship of the Son and the Spirit with the Father in the unity of the Godhead. From this, perhaps, we can begin to see how big and significant a thing the covenantal category is both in biblical teaching and in real life."
What three implications follow from covenant theology?
Packer again: (1) the gospel of God is not properly understood till it is viewed within a covenantal frame; (2) the Word of God is not properly understood till it is viewed within a covenantal frame; (3) the reality of God is not properly understood till it is viewed within a covenantal frame.
Packer says "the Bible 'forces' covenant theology on all who receive it as what, in effect, it claims to be -- God's witness to God's work of saving sinners for God's glory." In what sense does Scripture "force" covenant theology upon us?
(1) By the story that it tells; (2) by the place it gives to Jesus Christ in the covenant story; (3) by the specific parallel between Christ and Adam that Paul draws in Rom. 5:12-18; 1 Cor. 15: 21; (3) by the explicit declaring of the covenant of redemption, most notably (though by no means exclusively) in the words of Jesus recorded in the gospel of John.