The Law proves that sinners have no free will. Sinners have free will to sin, but no free will to keep the Law. “The point is not that you’ve sinned, but you’ve never done anything but sin.”
Everyone is a sinner (Romans 3:2).
Everyone is DEAD in sin (Romans 6:23).
No one can keep the Law (Romans 3:20).
Even our righteous acts are like filthy rags to God. (Isaiah 64:6).
The Law reminds about sin (Romans 7:7).
The Law in the OT is a shadow of Jesus (Hebrews 10).
So when Jesus came, He fulfilled the Law for us (Matthew 5:17).
Salvation is by grace alone, through faith alone, in Christ alone (Ephesians 2:8, Galatians 2:16).