Several false understandings of the law have been prevalent since the law was given. The most common error is the view that we can be made righteous through keeping the law. The Jews believed that they were special because the had the law. They also believed that the could gain righteousness by keeping the law.
Paul spent a large part of his ministry debunking this myth. Here are two statements that make his position clear.
If righteousness could be gained through the law, Christ died for nothing! (Gal 2:21).
Clearly no one is justified before God by the law, because, "The righteous will live by faith" (Gal 3:11).
The law cannot make us righteous. Only the ministry of Jesus can accomplish that goal.
However, although Paul was very hostile to those who claimed a righteousness through the law, he was careful not to denigrate the law itself. He said the law is spiritual, holy just and good (Rom 7). The law is good and holy when used for the correct purpose (1 Tim 1:7-9). It only becomes a problem when used as a basis for righteousness, something that it was not designed to do. True righteous can only be obtained through Jesus, and we appropriate his righteousness through faith.
Many Christians assume that there is something wrong with God's law. Paul was clever enough not to throw the baby out with the bath water. When the law is used for the wrong purpose, it is useless. However, when it is used for the correct purpose, it is still holy and just.
This begs the question: If righteousness comes through faith, and even Abraham understood this 400 years before the law, what is it for? Most Christian teaching describes the law as a temporay system of righteousness that did not work. That does not make sense, because God does not make mistakes.
God gave the law to restain crime. That was his purpose for the law. It never had any other purpose and that purpose has not changed.
The law cannot be replaced as a method for restraining wickedness. Everyone understands this. Even nations that reject God have laws against theft and violence. They mess up God's law by adding human accretions. The only thing that is finished for the law is the incorrect attempt to use it as a basis for righteousness.