Peter recognized that the writings of Paul, especially those explaining the law, could be hard to comprehend. He defines for us the primary problem with understanding some of apostle Paul's teachings.
And bear in mind that the longsuffering of our Lord is salvation, exactly as our beloved brother Paul, according to the wisdom given to him, has also written to you;
As he has also in all his epistles, speaking in them concerning these things; in which are some things that are difficult to understand . . . " (2Peter 3:15 - 16, HBFV throughout).
Paul, in no uncertain terms, tells us what he thinks of the law. He states, "Therefore, the law is indeed holy, and the commandment holy and righteous and good . . . " (Romans 7:12). The idea that believers who have faith abolish or no longer need God's law was a foreign concept to the apostle Paul.
Are we, then, abolishing law through faith? May it never be! Rather, we are establishing law (Romans 3:31).
All Scripture (including the Old Testament) is God-breathed and is profitable for doctrine, for conviction, for correction, for instruction in righteousness; So that the man of God may be complete, fully equipped for every good work (2Timothy 3:16).
According to Paul the law has a dual role. Its first role is to instruct or educate us concerning how our Father wants us to live our life. Its second role is to convict us of sin (the judicial role) and lead us to conversion through faith in Christ. Once converted this role is no longer needed. In Galatians, Paul tells the church to allow God to teach them, "Let me ask those of you who want to be subject to the Law: do you not hear what the Law says?" (Galatians 4:21).
By telling the church of God to pay attention to his law, the apostle is upholding its role to teach. Paul, however, also recognizes its judicial role. After stating Abraham's inheritance was given based on God's promise, Paul says,
What, then, was the purpose of the Law? It was added in order to show what wrongdoing is . . . (Galatians 3:19, TEV).
The law of God was "added," meaning that at Mt. Sinai it was given in a codified form, in order to identify sin. In the book of Romans Paul uses another analogy to discuss its judicial role.
In the same way, my brethren, you also were made dead to the marriage law of the Old Covenant by the body of Christ in order for you to be married to another, Who was raised from the dead, that we should bring forth fruit to God (Romans 7:4).
We, according to Paul, died to the law, meaning that its ability to identify us as sinners and demand our life in payment for our sins was fulfilled through the sacrifice of Jesus.
But now we have been released from the law because we have died to that in which we were held so that we might serve in newness of the spirit, and not in the oldness of the letter (Romans 7:6).
For those of us who are truly converted and have God spirit, the law can no longer identify and punish us as sinners. That said, the educative role of God's law calls for our obedience, which is fulfilled through the new life in the Spirit. That is what Paul means when he wrote in Romans 6 the following.
For sin shall not rule over you because you are not under law, but under grace (Romans 6:14).
The added rules
Some think that the law that was added due to sin (Galatians 3:19) concerned strictly the sacrificial system given to ancient Israel and not the Ten Commandments. While this line of reasoning seems plausible it is nonetheless not true. In Paul's writings he usually refers to "the law" in general. His constant reference to it in his epistle greatly weakens the idea of it being added.
Paul is, in fact, teaching that all of God's commands were "added" at Sinai. Although certain proscriptions against adultery, murder and so forth existed before Moses, what was given at Mt. Sinai had not existed in the form God gave it.
In other Biblical verses the apostle speaks of the law in its entirety, and not just the sacrifical piece of it (see Romans 5). The temple ceremonies and the sacrifices were a part it from the start.
According to Paul and many other Biblical writers, the perfect law of God is a wonderful blessing and not a curse! Sin is the curse! Obedience to our heavenly Father results in numerous blessings both now and forever.