Romans 7:4
Therefore, my brethren, you also have become dead to the law through the body of Christ, that you may be married to another—to Him who was raised from the dead, that we should bear fruit to God.
In this chapter Paul is talking to the Jews that know the law, and keep the law. He tells them that they will forever be slaves, or owned by the law. Unless they die to it. That is, unless they no longer live under the bondage of the law. So, he uses the example of a married woman being bonded to her husband until death. Only then could the woman remarry and begin a new life. During biblical time, if a woman were to become a widow with out a son, or with out a male family member to preserve her husbands name, she would be sent back to her father's house. That widow was no longer bonded to her husband's family. Nor was the woman considered to be an heir. She was totally free to marry another, and bear his children.
This is such a beautiful example of Paul's own journey that began on the road to Damascus. Paul was delighted with himself when it came to keeping the law. He followed it, he was faithful to it, and he never broke the law. Then he met Jesus on that road to Damascus. There he came to understand that the law could never make him righteous. This was a devastating truth for Paul. That is when Paul became that widow set free from the law, and that is when he married again unto Jesus Christ to bear fruit.
Our works could never make us righteous before God. At our very best our works of the law are as dirty rags. However, by committing ourselves to Jesus we also have a new relationship with God. We that are in Christ bear fruits of love, joy, peace, long-suffering, gentleness, goodness, and self restraint. These are fruits of righteousness that only blossom when we abide in Jesus.