How do we know that justification is by faith?

Paul makes it clear that justification comes through faith in Jesus Christ, not through adherence to the law (Galatians 3:24-26). The law's role is to highlight our failings, showing that we cannot achieve righteousness on our own. If we could attain life and salvation through the law, it would not have necessitated Christ's coming. Instead, the law serves as a pointer, guiding us towards faith in Christ, who fulfilled the law's requirements on our behalf. Thus, our justification is rooted in trusting Christ and His completed work, a crucial tenet of Reformed theology.