I have long found the various teachings about God’s covenant to be unnecessarily confusing. For instance, various people have identified the Covenant of Redemption, the Covenant of Grace, the covenant of freedom, and covenant of bondage (also called the covenant of works/law). It becomes difficult to understand how these various covenants relate to one another, and which ones are still in force or not. And trying to sort out the historical writings on God’s covenant(s) is quite difficult because the literature is long, detailed and various positions disagree.
A simpler covenantal taxonomy will help.
By grace alone God created man (humanity) and established them in His covenant. The context (garden) in which man was placed contained the two elements of God’s covenant: blessing (represented by the tree of life) and cursing (represented by the tree of knowledge (self determination of good and evil) [Genesis 2:9]. This two-sided covenant included all humanity and is eternal (Genesis 2:16-17).
This covenant has gone through various iterations, most of which emphasized God’s intention to bless humanity (Noah [Genesis 9:17], Abraham [Genesis 17:9], Moses [Exodus 34:27], David [2 Samuel 7:8-16], etc.). The essential structure of the covenant is delineated in Deuteronomy 28. The understanding that God’s eternal covenant includes both blessings for obedience and cursing for disobedience untangles much of the confusion. It underlines the unity and consistency of God’s unfolding covenant, and the fact that it applies eternally to all people.
As a consequence of Adam’s sin, all of Adam’s people are on the train to hell — because of God’s covenant. It is God’s covenantal jurisdiction that sends people to hell. People go to hell because of the stipulations of God’s covenant (cursing for disobedience), just as people go to heaven because of the stipulations of God’s covenant (blessing for obedience).
But Adam’s sin rendered (or demonstrated) that man alone could not live in obedience to God’s law. That is the central teaching of the Old Testament. So, God sent Jesus to replace Adam’s covenantal headship and live in perfect obedience, which satisfied God’s requirement for obedience. Christ died on the cross for Adam’s (humanity’s) sin, which satisfied God’s demand for justice. And Christ released the Holy Spirit to inhabit God’s people through regeneration, which did two things: 1) it satisfied God’s expression of grace/mercy, and 2) it guaranteed that those who were inhabited by the Holy Spirit would eventually (in glory) acquire Christ’s righteousness — which would release the fullness of God’s blessings. Those who are in Christ will complete their sanctification because that is Christ’s intention and He is God — and God accomplishes His own will.
So, Christ’s New Covenant is both a renewed covenant (God’s eternal covenant is still eternal), and a New Covenant because Christ is the New Covenant Head. Those who are caught up (reborn) in Christ’s New Covenant are guaranteed God’s ultimate blessings, not because of their own obedience or faithfulness, but because of Christ’s obedience and faithfulness. However, God’s blessings are not merely for individuals, but are for the corporate body of Christ (love requires others). Thus, there is not a one-to-one correspondence between individual faithfulness and blessings. But as the body of Christ continues to grow the blessings will also increase.