Can the law save anyone, or what does it do?
The law cannot save anyone. It has no power to save anybody; it only condemns and gives the knowledge of sin. Paul writes there is no justification by the law, and the righteousness of God is now without the law.
Les explains that under the Judaic system, Israel was to keep the law, and with the appearance of the Messiah an added responsibility was to believe He was the Christ, the fulfillment of all those Old Testament covenants. Yet it was still based on the Judaic system of law. But Paul says that by the law there is no justification, for the law is the knowledge of sin. Les emphasizes that the law does nothing, absolutely nothing, but condemn us; there is no power in the law to save anybody. Many people think that by doing the best they can and keeping the commandments they will make it, but if they only think or hope, they have already shown they do not know. Romans 3:21 marks a change: we are no longer under that Judaic system of the law, but now the righteousness of God is without the law.