Here is part of a letter John Newton wrote. In it, he discussed 1 Timothy 1.8.
“What [is it] to use the law lawfully? The expression implies, that it may be used unlawfully; and it is so by too many. It is not a lawful use of the law to seek justification and acceptance with God by our obedience to it: because it is not appointed for this end, or capable of answering it in our circumstances. The very attempt is a daring impeachment of the wisdom and goodness of God; for if righteousness could come by the law, then Christ has died in vain (Gal. 2.21), so that such a hope is not only groundless, but sinful; and, when persisted in under the light of the Gospel, is no less than a wilful rejection of the grace of God.”
“Again, it is an unlawful use of the law, that is, an abuse of it, an abuse both of law and Gospel, to pretend that its accomplishment by Christ releases believers from any obligation to it as a rule. Such an assertion is not only wicked, but absurd and impossible in the highest degree: for the law is founded in the relation between the Creator and the creature, and must unavoidably remain in force so long as that relation subsists. While he is God, and we are creatures, in every possible or supposable change of state or circumstances, he must have an unrivalled claim to our reverence, love, trust, service, and submission. No true believer can deliberately admit a thought or a wish of being released from his obligation of obedience to God in whole or part; he will rather start from it with abhorrence.”
“But Satan labors to drive unstable souls from one extreme to another, and has too often succeeded. Wearied with vain endeavors to keep the law, that they might obtain life by it, and afterwards taking with a notion of the Gospel devoid of power, they have at length despised that obedience which is the honor of a Christian, and essentially belongs to his character, and have abused the grace of God to licentiousness. But we have not so learned Christ.”
This excerpt was taken from Newton’s letter called “The Right Use of The Law.”