It seems that many think Jesus came to do away with the law. I can see why at a glance this is assumed but let us examine the purpose of the law and in particular the 10 commandment law.
Gal 3:24 Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
Gal 3:25 But after that faith comes, we are no longer under a schoolmaster.
First, we note the law was designed to lead us to Jesus that we could be justified by faith not works of the law but faith. Once this faith comes we no longer need the law to bring us to Christ because we are there.
So the first point is that the law was designed to bring us to Jesus to be saved by faith.
what function did the law play in order to do this?
Rom 3:19 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.
Rom 3:20 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.
The law reveals sin, notice that this is its function to reveal or make sin known. Its purpose is to bring us to Christ for salvation buts its function is to make sin known.
Is the law itself sin, if not how does it reveal sin?
Rom 7:7 What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law, had said, Thou shalt not covet.
Rom 7:12 Wherefore the law is holy, and the commandment holy, and just, and good.
Rom 7:13 Was then that which is good made death unto me? God forbid. But sin, that it might appear sin, working death in me by that which is good; that sin by the commandment might become exceeding sinful.
The law is not sin, but rather reveals or gives a knowledge of sin by showing what is good.
But we fall short of it and thus because we are breaking that law we know we are sinners.
So we know that the purpose of the law was to lead us to salvation in Christ, it does this by revealing that we are breaking the law and thus sinning. The law itself is good and holy and spiritual. The problem is we are not.
So then does this mean that sin only existed after the law was given?
Rom 5:12 Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
Rom 5:13 (For until the law sin was in the world: but sin is not imputed when there is no law.
Rom 5:14 Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come.
Notice death came by sin and death reigned form Adam to Moses. Thus sin was in the world before the law. as we have seen the law simply points it out so that we are without excuse:
Rom 3:19 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.
Rom 3:23 For all have sinned, and come short of the glory of God;
In Galatians it says it this way:
Gal 3:19 Wherefore then serveth the law? It was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator.
It was added because of transgression or in other words sin. So that all would be guilty and see their need of saving.
So we note that the law is good that it reveals sin and thus a need for a savior. We know sin was in the world before the law was added. All the law did was make us knowledgeable of that sin and thus under condemnation and in need of salvation in Christ.
This automatically tells us that Christ did not come to get rid of the law for it is good and spiritual. But rather he came to save from sin. The whole reason he gave the law was so we would see our sin and our need of saving.
Our problem is not the law, it has always been sin. The law had no power to free us form sin. Many tried to keep it by in their flesh but all failed as the law could not save but rather reveal our hopeless condition. Jesus gives us hope and faith. He offers what we could not do ourselves. He offers to free us from sin. that is why he came:
1Jn 3:8 He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose, the Son of God was manifested, that he might destroy the works of the devil.
1Jn 3:9 Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God.
Jesus makes us free form sin and thus the condemnation of the law. and thus the very law that condemned the hopeless sinner becomes a witness to those who are saved from sin by faith as it is written:
Rom 3:21 But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets;
The righteousness of God that is not by works of the law is witnessed by the law and the prophets. That the law is written on the heart. That the sinner has been saved from sin.
Where once thou shalt not kill condemned the sinner, now it witnesses to the one saved that he does not kill and thus is the righteousness that comes by faith.
Jesus is able to save us by his promises. praise God.