Joel Beeke
The Puritans, then, were not afraid to use the law of God as an instrument of evangelism. When God is about to play the chord of grace in the soul, they taught, he usually starts with the bass note of the law.

Have mercy on those who doubt; save others by snatching them out of the fire; to others show mercy with fear, hating even the garment stained by the flesh.
Jude 22-23