The function of the law has always been for the knowledge of sin. Romans 3:19-20 says:
“Now we know that what things soever the law saith, it saith to them who are under the law: that every mouth may be stopped, and all the world may become guilty before God. Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.” – Romans 3:19-20
For those who have no knowledge of their sinful nature or the consequences of their sin, the law is the proper tool to show their depraved condition.
Paul says in 1 Timothy 1:8 that ‘we know that the law is good, if a man use it lawfully’. In the dispensation of grace we must be careful to use the law lawfully, and not contrary to its purpose. Moses spoke of the law:
“For it is not a vain thing for you; because it is your life:…” – Deuteronomy 32:47
The very life and blessing of the nation of Israel depended on their response to the divine law in faith.
However, through the failure of Israel to follow the law, God revealed his hidden purpose and wisdom that the law had no power to save sinful humanity (Romans 3:19-20, 8:3). Indeed, it did nothing else but to manifest the wickedness of sin in our nature. (see ‘Am I good enough to go to heaven?‘)
Paul says, that the ‘law entered, that the offence might abound’; ’without the law sin was dead’; and ‘when the commandment came, sin revived, and I died’ (Romans 5:20, 7:9-10). This does not show that the law is wicked or evil, but on the contrary that WE are wicked and sinful.
For the ‘law is holy, and the commandment holy, and just, and good’, but we are ‘carnal, sold under sin’ (Romans 7:12-14).
We are held in bondage to the law, as it slays the sinfulness of our flesh, and puts us under the condemnation of God’s wrath. ‘The law worketh wrath’, and we who failed under the law were deserving of that wrath (Romans 4:15a).
Yet, while we were still sinners, God commended his love for us in that he sent his Son to take upon himself God’s wrath in our place (Romans 5:8-9). Giving us his own righteousness by faith, Jesus blotted out the ‘handwriting of ordinances that was against us’ (Col 2:14). He took our wages of death on the cross and satisfied God’s justice for sin (Romans 7:24-25, 8:2). The law no longer has its power over us unto death, for in Christ we are dead unto the law. ‘For where no law is, there is no transgression’ (Romans 4:15).
It is not that the law does not exist, or ceases to perform its function. It is that the law has no more hold over us, since we have been crucified and have satisfied the justice of the law in Christ!
“I am crucified in Christ: nevertheless I live, yet not I, but Christ liveth in me:…” – Galatians 2:20
Our penalty has been paid, our flesh is crucified, so the law has no effect. Christ enables us to serve him in righteousness by faith!
“Being then made free from sin [we become] the servants of righteousness.” – Romans 6:18
Once we are saved, God no longer looks at our sin, but at the righteousness we have been freely given through Christ’s redemption, even the righteousness of God.
The law has fulfilled its duty in bringing us to Christ. Subsequently, it is only by faith in Christ’s payment for our sins that we can be justified unto salvation.
“For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: not of works, lest any man should boast.” – Eph 2:8
The law then was not given to make us righteous, or encourage righteousness. By the law is the knowledge of sin; it manifests our unrighteousness. It was given as a schoolmaster to lead us into an understanding and appreciation of God’s grace.
“…the law is not made for a righteous man, but for the lawless and disobedient, for the ungodly and for sinners, for unholy and profane, for murderers of fathers and murderers of mothers, for manslayers, For whoremongers, for them that defile themselves with mankind, for menstealers, for liars, for perjured persons, and if there be any other thing that is contrary to sound doctrine;” – 1 Timothy 1:9-10
Understanding the function of the law helps us to appreciate the salvation we have by God’s grace. If it were not for the death, burial, and resurrection of Christ we would still be under the law, lost in our sins, and destined for God’s wrath and punishment.