Galatians 2:16 NIV

16 know that a person is not justified by the works of the law, but by faith in Jesus Christ. So we, too, have put our faith in Christ Jesus that we may be justified by faith in[a] Christ and not by the works of the law, because by the works of the law no one will be justified.

We don't need to prove anything, we just need to reposition our faith.