Learn hence the usefulness of the law to bring souls to Jesus Christ. It is utterly useless, as a covenant, to justify us; but exceeding useful to convince and humble us; it cannot relieve nor ease us, but it can and doth awaken and rouse us. It is a fair glass to shew us the face of sin, and till we have seen that we cannot see the face of Jesus Christ.
The law, like the fiery serpent smites, stings, and torments the conscience; this drives us to the Lord Jesus, lifted up in the gospel, like the brazen serpent in the wilderness, to heal us. The use of the law is to make us feel our sickness; this makes us look out for a Physician: “I was alive once, without the law, (saith Paul) but when the commandment came, sin revived, and I died,” Rom. 7:9. The hard, vain, proud hearts of men require such an hammer to break them to pieces.
 John Flavel, The Whole Works of the Reverend John Flavel, Volumes 1-6, vol. 2 (London: W. Baynes and Son, 1820), 180–181.