Covenant of Works
Edwards also posited a clear, binding covenant with the first Adam:
No. 30. COVENANT. With reference to what has been before spoken of the covenant [No. 2]. Covenant is taken very variously in Scripture, sometimes for a divine promise, sometimes for a divine promise on conditions. But if we speak of the covenant God has made with man stating the condition of eternal life, God never made but one with man, to wit, the covenant of works; which never yet was abrogated, but is a covenant stands in full force to all eternity without the failing of one tittle. The covenant of grace is not another covenant made with man upon the abrogation of this, but a covenant made with Christ to fulfill it. And for this end came Christ into the world, to fulfill the law, or covenant of works, for all that receive him.
No. 367. For Christ only fulfilled the covenant of works for us, and performed that obedience which Adam should have performed.
Covenant of Grace
Commissioned, as it were, in the covenant of redemption, the last Adam fulfills the stipulations of the covenant of works so that we might enjoy the benefits of the covenant of grace:
Every command that Christ obeyed may be reduced to that great and everlasting law of God that is contained in the covenant of works, that eternal rule of righteousness that God had established between himself and mankind. Christ came into the world to fulfill and answer the covenant of works, that is the covenant that is to stand forever as a rule of judgment, and that is the covenant that we had broken, and that was the covenant that must be fulfilled.
While the covenant of grace is inextricably bound with the covenant of redemption, it is nevertheless crucial to distinguish the two covenants:
No. 919. COVENANT OF REDEMPTION AND COVENANT OF GRACE.
Nos. 617, 825, 1091. If, by the covenant of grace, we understand the covenant between God the Father and men, [it] is no other than a revelation of part of the covenant of redemption to men, even that part of [it] that contains promises of blessings to men, renewing the same promises to believers as in Christ, and as it were parts of him, that had before been made to Christ for them; if it be understood as the covenant between Christ and believers, 'tis the marriage covenant. The covenant between God the Father and believers is, in some respect, the same with the covenant of redemption between the Father and the Son-as much as the covenant God made with Abraham, when he bid him depart out of his own country, etc., and made him such promises concerning himself and his seed, was the same with the covenant that God made afterwards in the wilderness with Abraham's seed. ’Tis no more than a revelation of part of a covenant made already, and renewing of the same promises over again.
Edwards was nothing if not careful and precise regarding his articulation of covenant theology. He even took issue with Thomas Boston’s (1676–1732) tendency to conflate the covenants of redemption and grace as though they were basically synonymous. Edwards understood that the conditions of obedience in the two were different and could not be fulfilled by the same parties. In the covenant of redemption, the task before Christ was to come to earth in obedience to the Father and obey what the first Adam had broken in the covenant of works. In the covenant of grace, the condition for the elect in Christ is faith in the mediator, who made the covenant of grace possible in the first place.
In all of this, the Trinitarian trajectory of Edwards becomes clear. God’s own eternal self-awareness, delight, and self-love, which brims over in intentional communication in creation, gloriously brings the elect into the society that is Father, Son, and Holy Spirit. On that great and last day, when the consummation of the covenant is manifest, the scope of this satisfaction is going to be staggering: “And now shall Christ the great Redeemer be most perfectly glorified, and God the Father shall be glorified in him, and the Holy Ghost shall [be] most fully glorified in the perfection of his work in the hearts of all the church.”