“The preaching of the law is most necessary. He that would ingraft, must needs use the pruning-knife. Sinners have many contrivances to keep them from Christ; many things by which they keep their hold of the natural stock; therefore they have need to be closely pursued, and hunted out of their skulking holes, and refuges of lies.
Yet it is the Gospel that crowns the work: ‘The law makes nothing perfect.’ The law lays open the wound, but it is the Gospel that heals it. The law ‘strips a man, wounds him and leaves him half dead:’ the Gospel ‘binds up his wounds, pouring in wine and oil,’ to heal them. By the law we are broken off, but it is by the Gospel we are taken up and implanted in Christ.”
Thomas Boston, Human Nature in its Fourfold State, pp. 281-282.