Thomas Goodwin contrasts them in this way:
This I will say in the general to you: there are two covenants, the covenant of grace, and the covenant of works, and these two are incompatible one with another. Take the law as it is a covenant, it is incompatible with the covenant of grace. These two are two vicegerents in man's heart; the law hath natural conscience in men's hearts to keep its courts, and the gospel hath faith in the heart to keep Christ's court. Now all men in the world, let them be never so much enlightened, and have not saving grace, they are under the law; therefore conscience is the supreme principle in them: all men that are godly are under grace, Rom. vii. 1, vi. 14; therefore they are under faith. Now here lies the great mystery of it: that still conscience would be the supreme principle, it would act according to the tenor of the law in a man's spirit, it would keep a man under the law; for it is true to its master which naturally it is appointed to serve, and doth oppose the dignity of faith, and therefore only God can so subdue conscience unto faith, as the law ought to be subdued to the gospel (The Works of Thomas Goodwin, II, pp. 346-7).