I really like how the Canons of Dort talks about the law and the gospel. It’s found in the 3rd and 4th points of doctrine:
Neither can the decalogue delivered by God to His peculiar people, the Jews, by the hands of Moses, save men. For though it reveals the greatness of sin, and more and more convinces man thereof, yet, as it neither points out a remedy nor imparts strength to extricate him from this misery, but, being weak through the flesh, leaves the transgressor under the curse, man cannot by this law obtain saving grace.
What, therefore, neither the innate understanding nor the law could do, that God performs by the operation of the Holy Spirit through the word or ministry of reconciliation; which is the glad tidings [good news] concerning the Messiah, by means whereof it has pleased God to save such as believe, as well under the Old as under the New Testament.
Covenant Presbyterian Church (OPC)
Hammond, WI, 54015