Z. Ursinus (d. 1583) said that all preachers should be able to clearly explain the difference between the Law and the Gospel. I say the same for the Covenant of Works and the Covenant of Grace distinction. Here is F. Turretin (d. 1687) on the difference between the two – this is part one of two.
1) They differ in the author: God is the author of both covenants, but in different relations. In the first (CoW) as Creator and Lord, and in the second (CoG) as Redeemer and Father. In the first (CoW) he was impelled by love and benevolence towards an innocent creature while in the latter (CoG) he was impelled by special mercy and grace towards a miserable creature.
2) They differ in the contracting parties: in the first (CoW), the parties were only two – God and man. In the first there was no need of a mediator because there was no sin. In the second (CoG) a mediator was needed to reconcile God and man. In the second, there is a third party — the Mediator.
3) They differ in the foundation: The CoW rested upon man’s obedience and strength of nature and free will. In the latter (the CoG), however, the foundation is Christ and his obedience. In the first man was in his own hands while in the second man is in the hand of God.
4) They differ in the promise: The CoW promised life as a due reward while in the CoW the promise of life is a gift of God.
5) They differ in the condition: in the first (CoW) the condition was “do this and live” while in the second “believe and you shall be saved.” In the CoW man would give a perfect righteousness while in the second man would receive it.
These five (out of 10) are found in Turretin’s Institutes, volume two page 190. Stay tuned for part two (with the last five differences).