Galatians 2:16:

Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.

See also:

What Mark 11:22 Really Means
What Galatians 2:20 Really Means
How to Be Saved from Your Sins