In The Ark of the Testament Opened (1681), Patrick Gillespie spends a good deal of time highlighting the similarities and differences between the covenants of works and of grace. In both covenants, God was the efficient cause; that is, He is the author of both covenants. In both, the moving cause is the grace of God. The goal of both covenants is the glory of God. If God’s grace was glorified in the first covenant, it was much more glorified in the person of His Son in the second covenant, which, by way of eminency, has the privilege of the title “covenant of grace.” In both cases, God enters into covenant with man. In each covenant, God provided strength or ability for the persons in covenant with Him to fulfill the conditions of the covenants. The two covenants also agree insofar as they are effectual toward the ends for which God made them. The covenant of works is still effectual after the fall as a way to curse and condemn men. The covenant of grace has an efficacy not present in the covenant of works because the Son of God places Himself under a covenant of works for the elect. The covenants of works and of grace also demand the same thing, namely, a perfect  righteousness that will enable the person to stand before the tribunal of God. The conditions in both covenants are set by God and not man. Both covenants had sacraments as signs and seals. Finally, Gillespie notes that in both covenants the “Confederates needed something more than habitual Grace, for fulfilling the conditions of these Covenants, and persevering in a Covenant-state of life.” In other words, perseverance in the garden would have been a supernatural grace given to Adam. In the same way, in the covenant of grace, believers need supernatural grace in order to persevere in the covenant.

Having discussed the similarities between the two covenants, Gillespie turns his attention to the differences between the two covenants, “which are manifold and substantial.” While both covenants are designed to advance the glory of God, they nevertheless differ in their special ends. The first covenant was made with man in innocency; he was to persevere in the garden through his obedience. The second covenant was made with sinful man in order to restore him to happiness. The end of the covenant of works was God’s glory as Creator, but in the covenant of grace, the goal is God’s glory as Redeemer. Returning to the matter of the “strength of perseverance,” Gillespie notes how the covenant of works was more dependent upon Adam and his natural strength, whereas in the covenant of grace believers are far more dependent upon God and His grace. Gillespie posits that the conditions of the first covenant were not any one act of obedience but rather multiple acts of obedience (i.e., perfect and perpetual). However, in the second covenant the initial act of a lively faith in Christ fulfills the condition of the covenant. Gillespie continues by stating, the ability to fulfill the conditions in the covenant of works was innate to Adam, but in the covenant of grace the conditions fulfilled by believers are not properly their own (Eph. 2:8; John 15:5).

 HT: As Identified by Patrick Gillespie: (1617–1675) in his work The Ark of the Testament Opened.