The law of God has one ministry, and the gospel has another. They do different things, and though both are important only one offers hope, freedom, cleansing, righteousness, and security. The gospel perfectly answers the law on our behalf.
The law says, “Thou art a sinner, and therefore thou shalt be damned;” Rom. vii. 2.; 2 Tess. ii. 12.
But the gospel says, No; “Christ Jesus came into the world to save sinners;” and therefore “believe on the Lord Jesus Christ, and thou shalt be saved,” 1 Tim. i. 15t Acts xvi. 31.
Again the law says, “Knowest thou not that the unrighteous shall not inherit the kingdom of God; be not deceived,” 1 Cor. vi. 9. And therefore thou being a sinner, and not righteous, shall not inherit the kingdom of God.
But the gospel says, “God has made Christ to be sin for thee, who knew no sin; that thou mightest be made the righteousness of God in him, who is the Lord thy righteousness,” Jer. xxiii. 6.
Again the law says, “Pay me that thou owest me, or else I will cast thee into prison,” Matt. xviii. 28. 30.
But the gospel says, “Christ gave himself a ransom for thee,” 1 Tim.ii. 6.; “and so is made redemption unto thee,” 1 Cor. i. 30.
Again the law says, “Thou hast not continued in all that I require of thee, and therefore thou art accursed,” Deut. xxvii. 6.
But the gospel says, “Christ hath redeemed thee from the curse of the law, being made a curse for thee,” Gal. iii. 13.
– taken from The Marrow of Modern Divinity